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GENESYS Version 6

Simulation

© Copyright 1986-1998

Eagleware Corporation4772 Stone DriveTucker, GA 30084

Phone: (770) 939-0156FAX: (770) 939-0157E-mail: [email protected]: www.eagleware.com

First PrintingPrinted in the USA

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TABLE OF CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . ixManual Organization . . . . . . . . . . . . . . . . . . . ixVersion 6.0 . . . . . . . . . . . . . . . . . . . . . . . . . ixGetting Started & Training . . . . . . . . . . . . . . . . . x

Chapter 1: Installation and Setup . . . . . . . . 1Hardware Keys . . . . . . . . . . . . . . . . . . . . . . . . 1Multiple Users Sharing Keys . . . . . . . . . . . . . . . . 2Software Installation . . . . . . . . . . . . . . . . . . . . 3Entering Authorization Codes . . . . . . . . . . . . . . . . 4S-parameter Data Files . . . . . . . . . . . . . . . . . . . 4Windows NT Installation . . . . . . . . . . . . . . . . . . 4Installing the Rainbow Device Driver . . . . . . . . . . . 5Installing the Aladdin Device Driver . . . . . . . . . . . . 6

Chapter 2: Starting . . . . . . . . . . . . . . . . 7The First Example . . . . . . . . . . . . . . . . . . . . . . 7Moving Markers . . . . . . . . . . . . . . . . . . . . . . . 9Tuning the Circuit . . . . . . . . . . . . . . . . . . . . . . 9Adjusting the Tune Percentage . . . . . . . . . . . . . . 10Updating the Tuned Trace . . . . . . . . . . . . . . . . . 11Saving Tuned Values . . . . . . . . . . . . . . . . . . . . 11Backup Files . . . . . . . . . . . . . . . . . . . . . . . . 11A Quick Look at Optimization . . . . . . . . . . . . . . 11Exiting =SuperStar= . . . . . . . . . . . . . . . . . . . . 12

Chapter 3: Using =SCHEMAX= . . . . . . . . . . 13Creating the Bridge-T Schematic . . . . . . . . . . . . . 14Schematic Text . . . . . . . . . . . . . . . . . . . . . . . 18Selecting Elements . . . . . . . . . . . . . . . . . . . . 19Deleting Elements . . . . . . . . . . . . . . . . . . . . . 20Zooming/Panning . . . . . . . . . . . . . . . . . . . . . 20Mirroring Elements . . . . . . . . . . . . . . . . . . . . 20Adding Comment Text to the Schematic . . . . . . . . . 20Using Substrates . . . . . . . . . . . . . . . . . . . . . . 21Using the Net Block to Reuse Networks . . . . . . . . . 21=SCHEMAX= Reference . . . . . . . . . . . . . . . . . . 22

Chapter 4: Window Blocks . . . . . . . . . . . . . 27WINDOW Block Syntax . . . . . . . . . . . . . . . . . . 28Network Specification . . . . . . . . . . . . . . . . . . . 29

Output Requests . . . . . . . . . . . . . . . . . . . . . . 30Output Request Reference . . . . . . . . . . . . . . . . . 30Frequency Sub-block . . . . . . . . . . . . . . . . . . . . 35Marker Sub-block . . . . . . . . . . . . . . . . . . . . . 40Optimize and Yield Sub-blocks . . . . . . . . . . . . . . 40Post Processing . . . . . . . . . . . . . . . . . . . . . . . 40Complex Terminations . . . . . . . . . . . . . . . . . . . 41Circles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Network Specification Overrides . . . . . . . . . . . . . 43Output Parameters . . . . . . . . . . . . . . . . . . . . . 43Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Chapter 5: Device Data . . . . . . . . . . . . . . 47Provided Device Data . . . . . . . . . . . . . . . . . . . 47Creating New Data Files . . . . . . . . . . . . . . . . . . 48File Record Keeping . . . . . . . . . . . . . . . . . . . . 50Using a Data File in =SuperStar= . . . . . . . . . . . . . 51Exporting Files . . . . . . . . . . . . . . . . . . . . . . . 52Noise Data in Data Files . . . . . . . . . . . . . . . . . . 52

Chapter 6: Optimization . . . . . . . . . . . . . 55Objective Function . . . . . . . . . . . . . . . . . . . . . 56The OPT Block . . . . . . . . . . . . . . . . . . . . . . . 58Optimization Example . . . . . . . . . . . . . . . . . . . 59Optimization Weights . . . . . . . . . . . . . . . . . . . 63

Chapter 7: Equations . . . . . . . . . . . . . . . 65Bandpass Filter With Equations . . . . . . . . . . . . . 65Using Equations in a Schematic . . . . . . . . . . . . . . 67Viewing Variable Values . . . . . . . . . . . . . . . . . . 68Function Definitions . . . . . . . . . . . . . . . . . . . . 68Equate Block Reference . . . . . . . . . . . . . . . . . . 70Algebraic Expression Format . . . . . . . . . . . . . . . 72Built in Function Definitions . . . . . . . . . . . . . . . 74Special Values . . . . . . . . . . . . . . . . . . . . . . . 75Sample Expressions . . . . . . . . . . . . . . . . . . . . 75Limits and Restrictions . . . . . . . . . . . . . . . . . . 75Logical Operators . . . . . . . . . . . . . . . . . . . . . . 76Reserved Words . . . . . . . . . . . . . . . . . . . . . . . 77

Chapter 8: User Models . . . . . . . . . . . . . . 79Using the Model Editor . . . . . . . . . . . . . . . . . . 79Using a Model in =SCHEMAX= . . . . . . . . . . . . . . 81Adding Models to the =SCHEMAX= Menus . . . . . . . 81

iv Table of Contents

Text Model Definitions . . . . . . . . . . . . . . . . . . . 83

Chapter 9: Statistical Functions . . . . . . . . . 85Example Monte Carlo Run . . . . . . . . . . . . . . . . 86Monte Carlo Setup . . . . . . . . . . . . . . . . . . . . . 90.MC File . . . . . . . . . . . . . . . . . . . . . . . . . . 92Worst Case vs. Monte Carlo . . . . . . . . . . . . . . . . 92Yield Block . . . . . . . . . . . . . . . . . . . . . . . . . 93Sensitivity Analysis . . . . . . . . . . . . . . . . . . . . 95Design Centering . . . . . . . . . . . . . . . . . . . . . 95Yield Optimization . . . . . . . . . . . . . . . . . . . . . 96Monte Carlo Screen Dumps . . . . . . . . . . . . . . . . 98

Chapter 10: EXPORT . . . . . . . . . . . . . . . 99Exporting Circuit Files . . . . . . . . . . . . . . . . . . 99Export Menu Overview . . . . . . . . . . . . . . . . . . 99Touchstone Export Example . . . . . . . . . . . . . . 100Exporting to Spice . . . . . . . . . . . . . . . . . . . . 102How Parts Translate to Spice . . . . . . . . . . . . . . 104Spice Command Text . . . . . . . . . . . . . . . . . . 106Equation Support . . . . . . . . . . . . . . . . . . . . 106Spice Device Naming Conventions . . . . . . . . . . . 107Spice Export and Analysis Examples . . . . . . . . . . 107Example 1 - File: SPICE1.SCH . . . . . . . . . . . . . 108Example 2 - File: SPICE2.SCH . . . . . . . . . . . . . 110Example 3 - File: SPICE3.SCH . . . . . . . . . . . . . 114Spice Scaling Factors and General Rules . . . . . . . . 118

Chapter 11: Examples . . . . . . . . . . . . . . 121

Chapter 12: Element Reference . . . . . . . . . 173Units . . . . . . . . . . . . . . . . . . . . . . . . . . . 173Circuit Block Reference . . . . . . . . . . . . . . . . . 173

Chapter 13: Printing and Plotting . . . . . . . 293Printing in Windows . . . . . . . . . . . . . . . . . . . 294Common Printing Questions . . . . . . . . . . . . . . 295

Chapter 14: Text Circuit Block . . . . . . . . . 299Circuit Block . . . . . . . . . . . . . . . . . . . . . . . 299Units . . . . . . . . . . . . . . . . . . . . . . . . . . . 302=SuperStar= Text Editor . . . . . . . . . . . . . . . . 302Editing Other Files . . . . . . . . . . . . . . . . . . . 304Editor Help . . . . . . . . . . . . . . . . . . . . . . . . 304

Table of Contents v

Leaving the Editor . . . . . . . . . . . . . . . . . . . . 304

Chapter 15: Menu Descriptions . . . . . . . . 305File Menu . . . . . . . . . . . . . . . . . . . . . . . . . 305Edit Menu . . . . . . . . . . . . . . . . . . . . . . . . . 307Tune Menu . . . . . . . . . . . . . . . . . . . . . . . . 308Optimize Menu . . . . . . . . . . . . . . . . . . . . . . 309Stats Menu . . . . . . . . . . . . . . . . . . . . . . . . 310Utils Menu . . . . . . . . . . . . . . . . . . . . . . . . 311Window Menu . . . . . . . . . . . . . . . . . . . . . . 312Export Menu . . . . . . . . . . . . . . . . . . . . . . . 313Layout Menu . . . . . . . . . . . . . . . . . . . . . . . 313Shell Menu . . . . . . . . . . . . . . . . . . . . . . . . 314Help Menu . . . . . . . . . . . . . . . . . . . . . . . . 314

Appendix A: S-Parameters . . . . . . . . . . . 315S-parameters . . . . . . . . . . . . . . . . . . . . . . . 315Sample S-parameter Data . . . . . . . . . . . . . . . . 319Stability . . . . . . . . . . . . . . . . . . . . . . . . . . 321Matching . . . . . . . . . . . . . . . . . . . . . . . . . 324Gmax And Msg . . . . . . . . . . . . . . . . . . . . . . 325The Unilateral Case . . . . . . . . . . . . . . . . . . . 326Gain Circles . . . . . . . . . . . . . . . . . . . . . . . . 327Noise Circles . . . . . . . . . . . . . . . . . . . . . . . 328Smith Chart . . . . . . . . . . . . . . . . . . . . . . . 329

Appendix B: How =SuperStar= Works . . . . . 333S-parameters . . . . . . . . . . . . . . . . . . . . . . . 334Two-port Interconnections . . . . . . . . . . . . . . . . 334Computer Execution Time . . . . . . . . . . . . . . . . 335Node Elimination Algorithm . . . . . . . . . . . . . . . 336Computational Classes . . . . . . . . . . . . . . . . . . 337Code Profiling . . . . . . . . . . . . . . . . . . . . . . 337Other Speed Enhancements . . . . . . . . . . . . . . . 338Circuit Simulator Types . . . . . . . . . . . . . . . . . 338=SuperStar= Models . . . . . . . . . . . . . . . . . . . 340Transmission Line Physical Models . . . . . . . . . . . 346Physical Model Example . . . . . . . . . . . . . . . . . 347When Are Physical Models Indicated? . . . . . . . . . 348Physical Model Execution Speed . . . . . . . . . . . . 350Related Physical Dimensions . . . . . . . . . . . . . . 350Optimized Physical Model . . . . . . . . . . . . . . . . 350

Appendix C: Drivers . . . . . . . . . . . . . . . 353

vi Table of Contents

Source Code . . . . . . . . . . . . . . . . . . . . . . . 354Code Description . . . . . . . . . . . . . . . . . . . . . 354PIMATCH Driver . . . . . . . . . . . . . . . . . . . . 355

Appendix D: SCH2CKT Program . . . . . . . . 357

Appendix E: Version 3.4 Files . . . . . . . . . . 359

Appendix F: References . . . . . . . . . . . . . 361

Appendix G: Error Messages . . . . . . . . . . 367Red Error Bar . . . . . . . . . . . . . . . . . . . . . . 367Displayed Error Messages . . . . . . . . . . . . . . . . 367Errors During Translation . . . . . . . . . . . . . . . 368=SuperStar= Operation Errors . . . . . . . . . . . . . 381=SCHEMAX= Errors . . . . . . . . . . . . . . . . . . 384Touchstone Translation Errors . . . . . . . . . . . . . 386Spice Translation Errors . . . . . . . . . . . . . . . . 391

Table of Contents vii

Introduction

=SuperStar= is a sixth generation linear circuit simulator.The program =SCHEMAX= provides easy schematic de-scription of your circuits and =LAYOUT= helps youquickly create PWB artwork and Gerber files. Eaglewarealso offers synthesis programs to assist you with the initialdesign of a wide variety of circuits. All of these synthesis,simulation, and prototyping tools are integrated into oneeasy to learn and easy to use family of products we callGENESYS.

MANUAL ORGANIZATION

The printed documentation for GENESYS consists ofthree manuals: Simulation, =LAYOUT= and Synthesis.You are reading the Simulation manual which describesthe =SuperStar= simulator and the =SCHEMAX= pro-gram.

VERSION 6.0

The first version of =SuperStar= was released in 1986.Version 6.0 was released in April 1997. From the begin-ning, =SuperStar= has been easy to use, interactive andfast. Another important aspect of the version history isupward compatibility. Any =SuperStar= circuit file youhave ever written will run in Version 6 with little or nomodification. Version 6 actually displays a suggestionmessage when a modification is required.

While maintaining these practical attributes, Version 6.0adds powerful new features including:

True multi-port analysis and descriptions (S45, S33, etc.)User modelingUser definable functions and inline equationsMore output optionsEasier exchange of data with other Windows applicationsYield OptimizationParameter sweeps (results vs. a component value)Excellon drill listsGain and noise circles, improved stability circlesImproved 3D plottingExpanded and updated device data librariesFantastic on-line hyper-text and hyper-graphics help

GETTING STARTED & TRAINING

Most customers are up and running quickly. =SuperStar=is packed with features; utilizing its full potential requiresexperience. But starting is easy.

We suggest that after installation you read the first exam-ple and follow along on your computer. It only takes a fewminutes and will save lots of time later. After that, if you’reanxious to analyze your own circuit, go ahead. Later,reviewing the manuals will help you discover advancedfeatures. Be sure to look at the Examples chapter. Itdescribes several interesting circuits and techniques.

Eagleware products are easy to use and we get few helpcalls. This is one reason why we do not charge for support.You will probably have a few questions at first, so feel freeto call. Soon you’ll be calling less and less. At times wefeel like the Maytag repairman. Also, be sure to takeadvantage of the new online help.

Custom training is available. This is most efficient ingroups of twenty or more users where the expense isshared and several users can benefit at once.

x Introduction

Chapter 1

Installation and Setup

HARDWARE KEYS

You must have a hardware key attached to your computerto run any Eagleware software. The hardware key is aphysical device that plugs into the parallel port of your PC(LPT1 or LPT2). It looks like a 25-pin NULL ModemAdapter or a Gender Changer. The combination of the keyand software encryption methods allow only your licensedsoftware to run. The other unlicensed programs will runin a limited demonstration mode, thus allowing you toevaluate these programs. If you decide to license any ofthem, call Eagleware and you can receive authorizationcodes to run the newly purchased programs immediately.

NOTE: Do not plug the key onto the back of a Zip or otherportable drive, as damage to the key may result. Alwaysplug the key directly onto the computer, in front ofportable drives.

To use the key, plug it onto your parallel port; the male sideof the key plugs into the female port of your computer. Thekey is designed to safely co-exist with most other hardwarekeys, as well as your printer cable connection. You mayplug your printer cable into the back of the key. If youexperience any printer problem or hardware key problemthat can be cured by removing the key, please contact usand let us know about the problem. The key must be

present while the software is running. Removing it willcause the program to abnormally terminate, which canresult in a loss of data. If you have any questions concern-ing the hardware key, please call us.

MULTIPLE USERS SHARING KEYS

Eagleware has a very flexible policy regarding the use ofsoftware by multiple users: you may install the softwareon as many systems as you want and must simply movethe hardware key around to the different systems whenyou want to use the software. For instance, this flexibilityallows you to legally use Eagleware software both at workand at home;you must just bring the key home on eveningswhen you want to use the software. Most software compa-nies are not this flexible, so it is not legal to bring mostother software home or install it on multiple systems.Also, if your company has strict software use policies, thekey provides an automatic monitor, since it is not possibleto use Eagleware software without it.

In a network environment, the key must still be pluggedinto the PC attempting to run Eagleware’s software, evenif the programs are stored on a network server; pluggingthe key into the network server will not allow a networkedPC to run Eagleware software.

If your company has several Eagleware keys, you maywant to setup your computers so that they all can use anykey. To do that, enter the authorization codes for all keysonto one system. This will not overwrite codes, but willadd them so that the system will allow all of the keys torun. Next, copy the KEYS.LST file from the C:\EAGLEdirectory to the C:\EAGLE directories on all other com-puters. (If you installed to a drive other than C, substitutethe correct drive letter in the preceding references.)

Note for advanced users: KEYS.LST is a text file, so if youhave already entered the codes onto your systems,you may

2 Installation and Setup

combine all the KEYS.LST files together in a text editorand copy the new file onto other systems.

SOFTWARE INSTALLATION

To begin installation, place the first GENESYS floppy diskor CDROM into your drive.

NOTE: You will need to use the actual drive letter of yourfloppy or CDROM drive. For example, if your CDROMdrive is D:, type D:\SETUP and press Enter to start thesetup program.

In Windows 3.1, select Run from the File menu in ProgramManager. Type A:\SETUP and press Enter to start thesetup program.

In Windows 95 or NT, select Run from the Start Menu.Type A:\SETUP and press Enter to start the setup pro-gram.

Follow the instructions on screen to finish the installation.

For a complete installation, the following directory struc-ture will be created during your installation:

C:\EAGLE\BIN Executable/binary filesC:\EAGLE\BIN\PROTO FILTER prototype filesC:\EAGLE\BIN\WINNT Windows NT driver filesC:\EAGLE\EXAMPLES Example filesC:\EAGLE\TEMP Temporary Eagleware filesC:\EAGLE\FONT =LAYOUT= fontsC:\EAGLE\MODEL User Model/Function directoryC:\EAGLE\LIB =LAYOUT= footprintsC:\EAGLE\SDATA S-Parameter data

For a network server installation, the following additionaldirectories will be created:

C:\EAGLE\WIN32S Win32s FilesC:\EAGLE\SETUP Workstation setup files. Run

Installation and Setup 3

SETUP.EXE from the users’computers to setup eachstation.

ENTERING AUTHORIZATION CODES

When you install your Eagleware software,you must enteryour Authorization Codes to activate your licensed Eagle-ware programs. If you decide to purchase one of our otherprograms, you will receive (via fax or mail) a new list ofAuthorization Codes. These codes allow you to run yournewly licensed Eagleware programs.

S-PARAMETER DATA FILES

S-Parameter data files are grouped into directories basedon company name and, in some cases, part types. TheS-Parameter data files were supplied by the part manu-facturers and compiled by Eagleware.

WINDOWS NT INSTALLATION

You must install a special Windows NT device driverbefore you will be able to run Eagleware’s programs underWindows NT. These drivers allow Windows NT to accessthe Hardware Key you have attached to your PC’s parallelport.

The procedure used depends on the type (manufacturer)of key you are using. With the release of Version 5.0,Eagleware products will be shipped with either a RainbowSentinel C+ key or an Aladdin MemoHASP key.

Which key do you have? Here is how you tell:

1) There are the physical color and size differences (L x W):

The Rainbow key has a gray body with silver coloredconnector housings, measuring 2 1/4" x 2 1/4".


The Aladdin key has a white body with brass coloredconnector housings, measuring 1 3/4" x 2 1/4" (some areeven smaller).

2) There are characteristic differences between the keysin the form of markings and printing :

The Rainbow key is blank except for the raised word^ COMPUTER ^ imprinted next to the male connector onthe top and bottom sides of the key body.

The Aladdin key has little finger-grip steps and arrows onboth the top and bottom sides. It also has the word HASPimprinted on the bottom of the key next to the maleconnector.

If you have a Rainbow Sentinel C+ key, go to Installingthe Rainbow Device Driver.

If you have an Aladdin MemoHASP key, go to Installingthe Aladdin Device Driver.

INSTALLING THE RAINBOW DEVICE DRIVER

You need to log on to your Windows NT machine withAdministrator or Power User privileges.

In Windows NT version 4.x, open the Control Panel andDouble-Click on Multimedia. Choose Unlisted or UpdatedDriver at the top of the list and click the OK button.

In Windows NT version 3.x, open the Control Panel andDouble-Click on “Drivers”. Choose Unlisted or UpdatedDriver and click the OK button.

Enter the path to the drivers located in C:\EAGLE-BIN\WinNT\RAINBOW directory. You may also browsethe directory name, which is similar to using an Open Filedialog box.

Once you have entered the correct path, you will get a listof Device Driver files. The list will read:

Installation and Setup 5

Sentinel for Alpha SystemsSentinel for i386 SystemsSentinel for MIPS Systems

You should choose the Sentinel for i386 Systems (meaningIntel 80386 class machines) driver and click the OK but-ton.

The Sentinel Device Driver screen will shortly appear withyour PC’s port information listed. It automatically deter-mines what parallel ports your machine has and sets upthe driver for you. You should click the OK button to acceptthe values and close the box.

Next, shutdown Windows NT and restart your PC. Youwill now be able to run your Eagleware programs (assum-ing you have attached your Rainbow hardware key to yourPC’s LPT parallel port).

INSTALLING THE ALADDIN DEVICE DRIVER

You need to log on to your Windows NT machine withAdministrator or Power User privileges. Run an NT-DOS/Command Prompt. This will place you at a DOScommand-line prompt under Windows NT. If you do nothave a Command Prompt Icon to run, then you can use theAlt+F/R (File/Run) menu option to run the programCMD.EXE. This will give you an NT-DOS prompt.

Change directories to C:\EAGLE\BIN\WinNT\ALAD-DIN. In this directory, type the command HINSTALL /iand press Enter. This will run the Aladdin HASP devicedriver installation program. It will display the messagetelling you the driver has been successfully installed.

Next, shutdown Windows NT and restart your PC. Youwill now be able to run your Eagleware programs (assum-ing you have attached your Aladdin hardware key to yourPC’s parallel port).


Chapter 2

Starting

T o start =SuperStar= in Windows 3.1, double-click the=SuperStar= icon. To start =SuperStar= in Windows95/NT, press the start button and select Pro-

grams/Eagleware V6.0/=SuperStar=.

THE FIRST EXAMPLE

In this example, a simple circuit is loaded, simulated, andtuned.

Select Open *.CKT File from the File menu. The “Open”dialog appears and the name of the desired file is re-quested.

Change to the EAGLE\EXAMPLES directory, select SIM-PLE, and press Enter. This is a three-element low-passfilter as shown in Figure 2-1. It has a 3-dB bandwidth of70 MHz.

=SuperStar= loads and translates this file. When =Super-Star= finishes translation, it displays the results of theanalysis in an output window. The output of SIM-PLE.CKT is shown in Figure 2-2.

In this case, two parameters were specified for output inone window. The forward transmission, S21, and the inputreflection coefficient, S11, are graphed on a rectangulargrid with a scale of -30 to 0 dB, or 3 dB per division. Thefrequency scale is 10 to 130 MHz, at 12 MHz per division.

1 2

0 0

L1

220 nH

C1

47 pF

C2

47 pF

Figure 2-1 Circuit used in the first example.

Figure 2-2 Simulated response for the first example.

8 Starting

NOTE: Everything in =SuperStar= is color-coded. Thecyan (light blue) trace corresponds to the cyan scalevertical axis on the left and the cyan markers below.

MOVING MARKERS

Notice that markers appear on the response trace. At thebottom of the screen, the frequencies and trace values ofthe markers are displayed. The frequency is displayed ontop and the trace values for each displayed parameter arebelow.

Click on the response window with the mouse. Now, youmay tune the frequency of the markers. Select a markerusing the left and right arrow keys. Step the markerfrequency up or down one sweep frequency position bytapping the up or down arrow key. A marker’s frequencycan be changed by typing a new frequency and pressingEnter. If the circuit was not analyzed at that frequency,=SuperStar= selects the nearest analyzed frequency anddisplays its marker value.

In the Utilities menu, there are several options that dealwith markers. The markers may be toggled off by selectingDisplay Markers. Markers are redistributed over the en-tire frequency range by selecting Redistribute Markers.You may save the frequencies of the markers in yourcircuit file by selecting Save Marker Blocks.

TUNING THE CIRCUIT

One of the most powerful features of =SuperStar= isreal-time tuning of values in your circuit file. The tuningarea is at the top of the screen, just below the menu. Tosee how tuning works, point and click on the tune area atthe top of the screen. (With just a keyboard, select GotoTune Area from the Tune menu).

Starting 9

The tunable elements of the lowpass filter are displayedin the tune area. The initial value of each component isunderneath each element identifier.

The commands for tuning are:

®¬ =Select Selects a component value to tuned¯ =Tune Up/Dn Steps a component value up or downF5 =SavesTrc Update solid tracesF7 = Increases step sizeF9 = Decreases step size

Press the key once. Press it again. Press it once more.You should have observed, on the screen, the effect of“tuning” the input capacitor, C,CAP1,0.

The new value of the capacitor is displayed under thatdesignator. The original results stay on the screen whilethe new results appear as dashed lines.

Press the ¯ key three times. This steps C,CAP1,0 downas many times as it was stepped up, returning C,CAP1,0to its original value.

Next press the ® key. The second element, L,IND1,2, ishighlighted. The inductor can now be tuned. Type 150and then press Enter. L,IND1,2 is now set to this newvalue. (This feature is used to make big changes quickly.It is also handy for setting a component on a standardvalue after a tuning session.)

ADJUSTING THE TUNE PERCENTAGE

The tune step size may be changed with the F7 and F9keys. The default step size is 5%. Pressing the F7 keyincreases the step size by a factor of two. F7 may bepressed again to further increase the step size. The F9 keydecreases the step size by a factor of two.

10 Starting

UPDATING THE TUNED TRACE

To update the trace to the tuned version, press F5. Thisdoes not change your circuit or schematic file. It onlyupdates the trace while you continue tuning. The screenmay be reinitialized to the original values at any time byloading in the values from the editor by selecting "Trans-late, Loading Values From Editor" from the Tuning menu.

SAVING TUNED VALUES

If you want to save values permanently, be sure to enterthe circuit (or schematic) editor after tuning or optimiza-tion. If you have selected “Auto-Replace” in the Tunemenu, the values are automatically replaced after enter-ing the editor. Otherwise, a dialog prompt confirms thatyou want to replace values before continuing. Until “Save”or “Save As” is selected from the File menu, all changesmade to component values or circuit text are temporary.You can undo any changes by simply reloading the filefrom disk. This is accomplished by selecting “Reload CKTfrom Disk” in the Tune menu.

BACKUP FILES

=SuperStar= automatically creates backup files. Thebackup file name is the same as the original file, with thefirst letter changed to a “~”. If you accidentally save a fileand want to restore the original, simply load the backup,and resave it over the original.

A QUICK LOOK AT OPTIMIZATION

Suppose we wish to reduce the attenuation at 70 MHz andlower frequencies, but to increase the attenuation athigher frequencies. The optimization targets are shownas dashed lines on the graph. To see how optimize works,reopen SIMPLE.CKT and select “Automatic” from theOptimize menu. Optimization begins immediately.

Starting 11

Within the circuit file SIMPLE.CKT are optimize targets.When an OPT is present in the circuit file, =SuperStar=automatically tunes the component values to try to satisfythese targets.

After a while, the attenuation up to 70 MHz is reduced toless than 1 dB. The attenuation at 130 MHz increases toalmost 15 dB.

A powerful feature of =SuperStar= is the ability for theuser to easily interact with the optimization process. Atany moment, you may temporarily halt optimization bypressing Esc. You may manually tune components andthen select “Automatic” from the Optimize menu to reac-tivate the optimization.

For more details on optimization, refer to Chapter 6.

EXITING =SUPERSTAR=

To exit =SuperStar= and return to Windows, select “Exit”in the File menu.

12 Starting

Chapter 3

Using =SCHEMAX=

M ost engineers will prefer to use =SCHEMAX= toenter circuits. Schematics allow for easier designdocumentation and verification than text circuit

files. The following bridge-T high-pass filter exampleillustrates how =SCHEMAX= works. See Figure 3-1 forthe schematic of this filter.

NOTE: If you have not purchased =SCHEMAX=, you maystill use it in demo mode, but you cannot save or printyour files. If you would like to purchase =SCHEMAX=,please contact Eagleware for an authorization code.

There are 3 steps involved in creating a new schematic:

1. Select “New” from the =SuperStar= File menu,and choose “Schematic” in the dialog box.

2. Place the schematic symbols, and assign the com-ponent labels and values.

3. Create the schematic’s text portion, defining the=SuperStar= output parameters and any equa-tions or tuning/optimization variables.

To edit an existing schematic, simply load the schematicfile by selecting “Open *.SCH File” from the =SuperStar=File menu, and start with step #2 above.

CREATING THE BRIDGE-T SCHEMATIC

=SCHEMAX= is designed to be quick and easy to use.Once you have followed this example, you will be able toenter your own schematic.

NOTE: If at any time you make a mistake and want todelete an element you have drawn, simply click on theelement with the mouse and then press Delete. Makesure you have highlighted only the item you wish todelete before you press Delete.

To enter the schematic:

1. Start =SuperStar= as described in Chapter 2.

2. Select “New” from the File menu. The “Select NewFile Type” dialog appears.

3. Press the “Schematic” button. The =SCHEMAX= edi-tor appears.

4. The yellow buttons at the top of the =SCHEMAX= win-dow contain groups of similar models. Press theLUMPED button to open a new toolbar containinglumped elements.

5. Press the RES (Resistor) button.

1 2 3

0

1 31 3

R1

50 ohm

R2

50 ohm

L1

120 nH

C1

47 pF

EXAMPLE1

Figure 3-1 BRIDGE-T.SCH

14 Using =SCHEMAX=

6. Click and hold the left mouse button inside thegrid area. Drag the mouse to the right and re-lease the button. A resistor appears.

7. Press the space bar. This reselects the resistor but-ton.

Tip: The space bar can always be used to repeat the lastpart placement. If the space bar is pressed repeatedly,=SCHEMAX= will cycle through the last ten componentsthat have been placed.

8. Click the left mouse button inside the circle on thelast resistor’s right terminal, drag to the rightand release the mouse button. A second resistorappears, connected to the first resistor.

9. Press the CAP (Capacitor) button on the toolbar.

10. Click and drag to place the capacitor above thetwo resistors, as shown in Figure 3-2. Note thatthe capacitor is not yet connected to the resistors.

11. Next, we will connect the capacitor:a. Click the gray 90 button on the top line of the

toolbar (this places a 90º connection).b. Click on the left node of the first resistor, drag

the connection to the left node of the capacitorand release the mouse button. Note: You must besure to drag up first (before dragging left) toorient the connection properly.

c. Press the space bar to place another wire, andclick and drag from the capacitor’s right node tothe right node of the second resistor. Note: Besure to drag right first (before dragging down).

12. Place the inductor by pressing the IND button,then clicking and dragging downward from be-tween the two resistors.

Using =SCHEMAX= 15

13. Press the gray GND (ground) button on the top lineof the toolbar. Click and drag downward from the in-ductor’s bottom terminal.

14. Press the INP (input) button (located next to the 90button). Click and drag leftward from the left resis-tor and release the mouse button. The INP dialogappears.

15. Type EXAMPLE into the Designator box, and clickOK. This names the network EXAMPLE.

16. Place the output by clicking the OUT button (locatednext to the INP button). Click and drag to the rightfrom the right resistor and release the mouse button.

The drawing of the schematic is now complete. This wouldbe a good time to save your file by selecting “Save” fromthe File menu. Next, the component values must be en-tered:

Figure 3-2 Partially drawn bridge-T schematic.

16 Using =SCHEMAX=

17. Select the capacitor you have drawn by clickingon it once.

18. Select “Details” from the Edit menu (or press F4).This will open the capacitor’s dialog box.

Tip: Double-clicking on an element will also open thedialog box.

19. Type C1 into the Designator field and press Tab,and type 47 into the Capacitance field. Leavethe Capacitor Q field empty.

20. Press OK to close the dialog box.

21. Open the left resistor’s dialog box (as above). TheRES dialog appears. Type R1 into the Designa-tor box and 50 into the Resistance box and pressOK. Repeat for R2 (the right resistor), and as-sign it a value of 50 also.

22. Open the inductor’s dialog, and assign it a desig-nator of L1, and a value of 120.

23. Press Esc to leave the schematic editor. (If auto-translate is not on, a question about translatingwill appear; answer yes.) The Add Window Blockdialog box will appear.

24. The fields in the dialog box should be the same asthose in Figure 3-3. Change any entries asneeded and press OK.

You should now see a graph similar to the one in Figure3-4. If you receive an error message or want to change theschematic or response type, return to =SCHEMAX= byselecting the “Edit Ckt File” option in the File menu.

Using =SCHEMAX= 17

SCHEMATIC TEXT

Once a schematic is entered, a text block must be enteredto tell =SuperStar= what to display. In step 24 above, thistext block was generated automatically. To view the textthat was generated, select Edit Ckt File from the Filemenu to enter =SCHEMAX=. Select Edit Ckt File fromthe File menu again to enter the =SuperStar= Text Editor.You will see the following text:

WINDOWEXAMPLE(50)GPH S21FREQSWP 0 100 101

This text requests that the magnitude of S21 in dB fromnetwork EXAMPLE (terminated with 50 ohms) begraphed from 0 to 100 MHz, with 101 sample points. SeeChapter 4, Output Formats, for more information on writ-ing window specifications.

Figure 3-3 Output of example circuit.

18 Using =SCHEMAX=

SELECTING ELEMENTS

Objects must be selected before they can be manipulated.An object is shown in red when it is selected.

To select a single element:

1. Be sure that no buttons on the tool bar are high-lighted. (If any are highlighted, press Esc.)

2. Click on the element to select with the left mousebutton.

To select multiple elements by drawing a rectangle aroundthem:


2. Click and hold the left mouse button in an openspace on the schematic. (If there are no conven-ient open spaces, you may press the BLK buttonon the toolbar before this step.)

3. Drag the mouse until a box is drawn which com-pletely surrounds the items to be selected.

4. Release the mouse button.

To individually select multiple elements:


2. Hold down Shift while clicking on elements to se-lect or deselect.

To select an element which is behind other elements:


2. Click on the element to select with the left mousebutton.

Using =SCHEMAX= 19

3. Continue clicking in the same spot until the desiredelement is selected. Do not click too fast (double-click), or an element dialog box will be displayed.

DELETING ELEMENTS

To delete elements from the schematic:

1. Select the element(s) which you want to delete.

2. Press the Delete key.

ZOOMING/PANNING

You can zoom in or out using the green buttons on thetoolbar (P,M,+,R,-) or the keyboard (Ctrl+End,Ctrl+Home,Ctrl+PgUp, Ctrl+PgDn). You can scroll the schematicusing the scroll bars or using the keyboard (Ctrl+Arrows).

MIRRORING ELEMENTS

You may want to mirror the position of the labels and theelements. To do so, select an element with the mouse.Press F6 until the element is in the desired position.There are a maximum of four positions to choose from.Note: Mirroring is most important for changing the orien-tation of components like BIP (bipolar transistor) and OPA(operational amplifier).

ADDING COMMENT TEXT TO THE SCHEMATIC

Writing text on the circuit can be done by selecting theTXT button. You must specify whether you want to justifythe text to the left, center or right. Then click with themouse at the position where you want the text placed. Abox will be displayed and you may type in your text.

USING SUBSTRATES

If your schematic contains any elements which use asubstrate (such as microstrip, stripline, coax, and

20 Using =SCHEMAX=

waveguide), then you must add one or more substrates toyour circuit file before it can be analyzed. To add or editsubstrates, select “Substrates” from the Edit menu. Youcan press F1 from the substrates dialog box for online helpwith details about this box.

USING THE NET BLOCK TO REUSE NETWORKS

Sometimes it is convenient to use a network more thanonce in a larger circuit. In Figure 3-4, for example, theMATCHAMP network is used twice within the largerBALANAMP network. The symbols for reusing networksare accessed from the NET button. To reuse a network:

1. Press the gray NET button on the top toolbar line.

2. Select the number of ports on the network to bereused.

3. Click and drag to place the NET symbol on theschematic.

4. Double-click the NET symbol to open the part dia-log box, and enter the network’s name to reuse.

1 2

0 0

2

6

0

6 6 10

0 0

1

10

15 16 17

17

19

15 21 19

15 15

17

19

17 2817

19

31

0

19 34

0

36

31

36

31

36

31

36

31 44 45

36 47 45

45 45

L1

2.9 nH

C1

3.9 pF

C2

10 pF

Q1

L2

5.4 nH

C3

1.5 pF

C4

3.3 pFMATCHAMP(1)

TL1

78 ohm30°

TL2

90 ohm38°

R1

100 ohm

TL1

78 ohm30°

TL2

90 ohm38°

BALANAMP(1)C5

0.5 pF

TL3

48 ohm100°

(2)

MATCHAMP

MATCHAMP TL3

48 ohm100°

R2

100 ohm

C6

0.5 pF

TL2

90 ohm38°

TL1

78 ohm30°

TL2

90 ohm38°

TL1

78 ohm30°

(2)

Figure 3-4 NET block example. The top network (MATCHAMP)has been used twice in the bottom network (BALANAMP).

Using =SCHEMAX= 21

=SCHEMAX= REFERENCE

Keyboard Commands

F2 Saves fileF3 Rotates selected elementF4 Displays/edits element designator and valuesShift+F4 Displays/edits all element designators, valuesF5 Toggles grid on and offF6 Mirrors the selected element and designatorF7 Toggles node zone junctions on and offF8 Displays text editor windowF9 Translates schematicF10 Activates menu barShift+Del Cuts the selected elementsCtrl+Ins Copies the selected elementsShift+Ins Pastes the selected elementsCtrl+D Duplicates the selected element(s)Ctrl+End Zooms to view the printed page (P button)Ctrl+Home Zooms the circuit to fit the screen (M button)Ctrl+PgUp Zooms in (+ button)Ctrl+PgDn Zooms out (- button)Arrow keys Move selected elements 1 grid spaceCtrl+Arrow Scrolls circuit pageSpace Bar Reselects recently selected element buttons

Button Abbreviations

P Zoom to pageM Zoom to circuit+ Zoom inR Zoom to rectangle- Zoom outBLK Selectes a group of elements—- (Line) Straight connection line90 90° connection lineINP Network inputOUT Network outputTXT Text (comments)GND Ground (node 0)

22 Using =SCHEMAX=

SIG Signal (ground in frequency domain)NET Reuse network

Lumped

RES ResistorCAP CapacitorIND InductorIND(PHYS) Aircore, spiral, and toroid inductorsIDEAL Circulator, delay, gain, isolator, and phaseANT Monopole and dipole antennae.MUI Mutually coupled inductors (transformer)TFC Thin film capacitorTFR Thin film resistorTRF Ideal transformerTRFCT Center tapped transformerXTL Piezoelectric resonator (crystal)

Device

ONE,TWO, Read S- or Y-parameter data for active orTHR,FOU,NPO passive devicesBIP Bipolar transistor (BIP_NPN, BIP_PNP)CCC Current controlled current sourceCCV Current controlled voltage sourceFET Transistor (N_FET, P_FET)GYR GyratorPIN PIN DiodeOPA Operational amplifierVCC Voltage controlled current sourceVCV Voltage controlled voltage source

T-Line

TLE Transmission line (electrical parameters)TLE4 Four terminal transmission line (electrical

parameters)TLP Transmission line (physical parameters)TLP4 Four terminal transmission lineCPL 2 coupled linesCPN N-coupled lines

Using =SCHEMAX= 23

RCLIN Distributed RC lineRIBBON Ribbon lineTLRLDC Distortionless TEM lineTLRLGC Uniform TEM lineTLX Exponential TEM lineWIRE Regular wire

Coax

CEN Coaxial endCGA Coaxial gapCLI Coaxial lineCLI4 Four terminal coaxial lineCST Coaxial step

Mstrip (Microstrip)

MLI Microstrip lineMCP Microstrip 2 coupled linesMCN Microstrip n-coupled linesMBN Microstrip bendMCR Microstrip cross junctionMCURVE Microstrip curved lineMEN Microstrip endMGA Microstrip gapLC Microstrip inductors and capacitorsMRS Microstrip radial stubMST Microstrip stepMTAPER Microstrip tapered lineMTE Microstrip tee junctionMVH Microstrip via hole

Slabline

RLI SlablineRCP Slabline 2 coupled linesRCN Slabline n-coupled lines

Stripline

SLI StriplineSCP Stripline 2 coupled lines

24 Using =SCHEMAX=

SCN stripline n coupled linesSBN Stripline bendSEN stripline endSGA Stripline gapSSP Stripline stepSTE Stripline tee junction

Wave (Waveguide)

WAD Waveguide adapterWLI Rectangular waveguide

Using =SCHEMAX= 25

Chapter 4

Window Blocks

A ll circuit files (both text and schematic) require atleast one window block. These blocks can be createdautomatically with the Add Window Block dialog

box, or can be typed in and edited manually.

Window blocks control the =SuperStar= analysis. Theycontain the following information:

• Network name and terminations for display

• Graph or table specifications

• Frequency and parameter sweeps

• Marker locations (optional)

• Optimization targets (optional)

• Yield targets (optional)

A very simple window block is shown in table 4-1. The firstline is WINDOW. All window blocks must start with thiskeyword.

WINDOWEXAMPLE(50)GPH S21FREQSWP 0 100 101

Table 4-1 A simple WINDOW block

The second line is EXAMPLE(50). This indicates thenetwork to analyze with its terminations. In this case, thenetwork EXAMPLE will be analyzed using 50 ohm termi-nations at all ports.

The third line is GPH S21. This line asks for a rectangu-lar graph of S21 versus frequency. The graph will autos-cale the Y axis.

The fourth line is FREQ. This line starts the fre-quency/parameter sweep sub-block. It is required in allwindow blocks.

The last line is SWP 0 100 101. This line specifies thefrequencies for analysis. With the SWP statement, thefirst number (0) is the start frequency in MHz, the secondnumber (100) is the stop frequency, and the last number(101) is the number of points to analyze. With this block,frequency points are 0,1,2...98,99,100 MHz, for a total of101 points.

WINDOW BLOCK SYNTAX

The window block has the following format:

WINDOWNetwork SpecificationOutput RequestsFREQFrequency Sub-Block[ MARKERMarker Sub-Block ][ OPTOptimize Sub-Block ][ YIELDYield Sub-Block ]

The sections in italics will be described individually in thefollowing sections. Those blocks in brackets [ ] are op-tional.

28 Window Blocks

WINDOWNetwork SpecificationOutput RequestsFREQFrequency Sub-Block[ MARKERMarker Sub-Block ][ OPTOptimize Sub-Block ][ YIELDYield Sub-Block ]

NETWORK SPECIFICATION

The line immediately following WINDOW must alwayscontain a network specification. The general format of anetwork specification is:

Network(Terminations)

Network is the name of the network to analyze. This is thename assigned to the input (INP) in a schematic or thename used with a DEFnP line in a circuit file.

Terminations describes the terminating impedances usedfor the network. Multiple terminations can be used,thereby terminating each port with a different impedance.If only one termination is given, it is used for all ports.

Some typical network specifications are:

EXAMPLE(50) ‘Terminate EXAMPLE with 50‘ohms at all ports

FILTER(50,100) ‘Terminate FILTER with 50‘ohms at the input and 100‘ohms at the output.

SPLITTER(50,100,100) ‘Terminate SPLITTER with‘50 ohms at port 1 and with‘100 ohms at ports 2 and 3.

Window Blocks 29

Network specifications can also contain post processingand/or complex termination commands. These topics arecovered later in this chapter in the Complex Termina-tions section.

OUTPUT REQUESTS

=SuperStar= can display output data in several differentways. The available output formats are:

• Rectangular Graph (GPH or LOG)

• Smith Chart (SMH)

• Polar Chart (POL)

• Three Dimensional Plot (G3D or L3D)

• Tabular (text) Listing (DSP)

Each window block corresponds to one window in =Super-Star=. A window may contain either a table or one or twographic outputs. The following rules apply to output datarequests:

• Each window may have either one table (DSP) or one ortwo graphic outputs (GPH, LOG, SMH, POL, G3D, L3D).

• Each graphic output may have one or two parametersplotted.

• The two graphic outputs do not need to be the same type.For example, two GPH requests and two SMH requestscould be used.

• Three dimensional graphs (G3D or L3D) cannot becombined in the same window with other graphic outputs.

OUTPUT REQUEST REFERENCE

Format: DSP parm1 [parm2 ]...

DSP is used to display a table containing results. Anyoutput parameters (described at the end of this chapter)can be shown in a DSP window.

30 Window Blocks

If DSP is used in a window, then only one line can be usedfor the output requests; multiple DSP lines are not al-lowed. Example window block containing DSP:

WINDOWFILTER(50,50)DSP SPAR GD[S21]FREQSWD 0 100 1

The following output parameters are used exclusively forDSP:

SPAR - Display all S-parametersHPAR - Display all H-parameters (2-port only)YPAR - Display all Y-parametersZPAR - Display all Z-parametersIMPED - Display impedances at all portsADMIT - Display admittances at all portsVSWR - Display VSWR at all ports

More example DSP lines:

DSP SPAR ‘Display all S-parameters indB/angle form.

DSP MAGANG[ZPAR] ‘Display all Z parameters in‘linear magnitude/angle form.

DSP KST B1 SB1 SB2 ‘Display stability parameters K‘and B1, and display coordinates‘for input and output stability‘circles.

Format: GPH parm [minimum maximum]Format: LOG parm [minimum maximum]

Both GPH and LOG create rectangular graphs. GPH plotsresults with a linear frequency/parameter scale whileLOG plots results with a logarithmic frequency/parameterscale. Minimum and maximum are used to scale the Y(vertical) axis. If they are not specified, the graph willautoscale.

Window Blocks 31

Each rectangular graph may plot one or two parameters.Any real values may be plotted. Complex values areconverted to real values using the following rules:

• Complex numbers in dB/angle (DBANG) format plot the DBportion by default.

• Numbers in linear magnitude/angle (MAGANG) format plotthe magnitude.

• Numbers in rectangular (RECT) format plot the real portion.

Example window block containing GPH and LOG:

WINDOWAMP(50)GPH S21 -20 0 ‘Graph DB[S21], scale -20 to 0GPH ANG[S11] ‘Graph ANG[S11], autoscale.LOG QL[S21] ‘Graph QL[S21], autoscale.LOG GMAX 0 20 ‘Graph GMAX, scale 0 to 20FREQSWD 0 100 1

Format: POL parm [scale]

POL plots vector data and circles to a polar chart. Scalespecifies the radius of the polar chart. For a unity radiuschart, use a scale of one with linear magnitude parametersand zero with dB parameters. Specification of other val-ues expands or compresses the plot. If the scale is notspecified, the graph will autoscale.

Although the underlying grid is different, plots are iden-tical on a polar chart and a Smith chart.

Each polar chart may plot one or two parameters. Anycomplex or circle values may be plotted. (See the circlesection later in this chapter for information on circles.) Ifa real value is specified, it is displayed in the marker text,but the corresponding complex value is displayed. Forexample:

POL ANG[S21]

32 Window Blocks

will display S21 in dB/angle form on the polar chart, butwill display the angle of S21 in the marker text area.

Format: SMH parm [scale]

SMH plots S-parameters or circles to a Smith chart. Scalespecifies the radius of the Smith chart. For a standard,unity radius chart, do not specify a scale. Specification ofvalues expands or compresses the plot. If two parametersare plotted on the same Smith Chart, then they both mustuse the same scale.

Although the underlying grid is different, plots are iden-tical on a polar chart and a Smith chart.

Each Smith chart may plot one or two parameters. OnlyS-parameters, GOPT, GM1, or circles may be plotted. If areal value is specified, it is displayed in the marker text,but the corresponding complex value is displayed. Forexample:

SMH ANG[S11]

will plot S11 on the Smith chart, but will display the angleof S11 in the marker text area. Additionally the followingconversions are made:

Impedance (I11, I22...) Plot S11, S22,...

Admittance (A11, A22...) Plot S11, S22,...

VSWR (V11, V22...) Plot S11, S22,...

YOPT or ZOPT Plot GOPT

YM1, ZM1, YM2, or ZM2 Plot GM1 or GM2

For more information on output parameters, see the sec-tion on Output Parameters later in this chapter.

Format: G3D parm [minimum maximum]Format: L3D parm [minimum maximum]

Both G3D and L3D create rectangular graphs. G3D plotsresults with linear frequency and parameter scales while

Window Blocks 33

L3D plots results with logarithmic frequency and parame-ter scale. Minimum and maximum are used to scale theY axis. If they are not specified, the graph will autoscale.

3D graphs are used either to plot a parameter versus bothfrequency and a swept variable or to plot a parameterversus two swept variables.

Each 3D graph may plot only one parameter. Any realvalues may be plotted. Complex values are converted toreal values using the following rules:

• Complex numbers in dB/angle (DBANG) format plot the DBportion by default.

• Numbers in linear magnitude/angle (MAGANG) format plotthe magnitude.

• Numbers in rectangular (RECT) format plot the real portion.

Example window block containing G3D and L3D:

WINDOWAMP(50)G3D S21 -20 0 ‘Graph DB[S21], scale -20 to 0L3D QL[S21] ‘Graph QL[S21], autoscale.FREQPRM C1 1 3 21 ‘Sweep C1 from 1 to 3 w/21 pts.SWD 0 100 1

3D graphs must have at least two sweeps specified in thefrequency sub-block. If a plot of parameter versus twoswept variables is desired, then three lines must be usedin the frequency sub-block: two parameter sweeps and onefrequency point. For example:

WINDOWAMP(50)G3D S21 -20 0 ‘Graph DB[S21], scale -20 to 0FREQPRM C1 1 3 21 ‘Sweep C1 from 1 to 3 w/21 pts.PRD C2 5 15 .5 ‘Sweep C2 from 5 to 15 every .5DIS 50 ‘Analyze at 50 MHz

34 Window Blocks

This example plots a graph of DB[S21] vs. C1 vs. C2 at 50MHz.

FREQUENCY SUB-BLOCK

All frequencies are specified in megahertz . Zero mega-hertz may be specified but will be calculated using 1 Hzby =SuperStar= to prevent over and under flows. Verylow frequencies may cause math errors (shown as a redstatus bar) when using physical models (such as mi-crostrip). If this occurs, start sweeping with a higherfrequency.

Each window block must contain a frequency sub-block.The frequency sub-block is preceded with FREQ. Gener-ally, this sub-block only contains one line starting witheither DIS, SWD, SWP, or SWL. However, if a parameteris to be swept or a 3D graph is requested, then multiplelines can be used.

DIS

Specifies discrete sweep frequencies in MHz.

Format:DIS freq1 freq2 freq3 freq4 . . . freqn

Each frequency to be run is specified. Each frequencyshould be greater than the previously specified frequency.The DIS list may continue on following lines by precedingeach following line with an &. For example:

DIS 51.75 57.75 63.75 69.75 75.75 81.75 87.75 93.75& 99.75 105.75 111.75 117.75 123.75 129.75 135.75& 141.75 147.75 153.75 159.75 166.74 173.75

SWD

Specifies a sweep frequency range with delta step size inMHz.

Window Blocks 35

Format:SWD start-freq stop-freq delta

For example,

SWD 100 200 .5

sweeps from 100 to 200 MHz with points every 0.5 MHz,a total of 201 points.

SWL

Specifies a sweep frequency range in MHz with logarith-mic steps. SWL is normally used with LOG or L3D forgraphic output.

Format:SWL start-freq stop-freq points-per-decade

If the number of points per decade is ten or less, then thefollowing multipliers are used to calculate the analysisfrequencies in each decade:

1 12 1, 33 1, 2, 54 1, 2, 3, 65 1, 1.5, 2.5, 4, 66 1, 1.5, 2, 3, 5, 77 1, 1.5, 2, 3, 4, 5, 78 1, 1.2, 1.8, 2.5, 3, 4, 6, 89 1, 1.2, 1.6, 2, 3, 4, 5, 6, 810 1, 1.2, 1.6, 2, 2.5, 3, 4, 5, 6, 8

If the number of points per decade is eleven or more, thenan exponential formula is used to calculate the multipli-ers.

For SWL, the start frequency must not be zero. Thestart frequency is not restricted to even decades. The lastfrequency is always a power of ten times the start fre-quency and may exceed the specified stop frequency.

36 Window Blocks

Examples:

SWL 100 10000 1Analysis occurs at: 100 1000 10000

SWL 1 1000 2Analysis occurs at: 1 3 10 30 100 300 1000

SWL 6 600 3Analysis occurs at: 6 12 30 60 120 300 600

SWP

Specifies a sweep frequency range in MHz and number ofpoints.

Format:SWP (start freq) (stop freq) (number of points)

TIP: When the end points of a sweep are included, anextra point is required for rational number step sizes.For example, sweeping from 100 to 150 MHz in 10 MHzsteps requires six points. The six frequency points are100, 110, 120, 130, 140 and 150 megahertz.

For example,

SWP 100 150 6

sweeps from 100 to 150 MHz with 6 points (every 10 MHz).

PRI

Specifies discrete parameter values.

Format:PRI variable value1 value2 value3 ... valuen

Each variable value to be run is specified. Each valueshould be greater than the previously specified value. ThePRI list may continue on following lines by preceding eachfollowing line with an &. For example:

Window Blocks 37

PRI C1 51.75 57.75 63.75 69.75 75.75 81.75 87.75& 93.75 99.75 105.75 111.75 117.75 123.75 129.75& 135.75 141.75 147.75 153.75 159.75 166.74 173.75

The variable specified must be a tuned value, ideally fromthe equate block.

PRD

Specifies a parameter sweep range with delta step size.

Format:PRD variable start-value stop-value delta

For example,

PRD Gamma 0 1 .01

sweeps gamma from 0 to 1 with points every .01, a total of101 points. The variable specified must be a tuned value,ideally from the equate block.

PRL

Specifies a parameter sweep range with logarithmic steps.PRL is normally used with LOG or L3D for graphic output.

Format:PRL variable start-value stop-value points-per-decade

If the number of points per decade is ten or less, then thefollowing multipliers are used to calculate the analysispoints in each decade:

1 12 1, 33 1, 2, 54 1, 2, 3, 65 1, 1.5, 2.5, 4, 66 1, 1.5, 2, 3, 5, 77 1, 1.5, 2, 3, 4, 5, 78 1, 1.2, 1.8, 2.5, 3, 4, 6, 8

38 Window Blocks

9 1, 1.2, 1.6, 2, 3, 4, 5, 6, 810 1, 1.2, 1.6, 2, 2.5, 3, 4, 5, 6, 8

If the number of points per decade is eleven or more, thenan exponential formula is used to calculate the multipli-ers.

For PRL, the start value must not be zero. The startvalue is not restricted to even decades. The last value isalways a power of ten times the start value and may exceedthe specified stop value.

Examples:

PRL R 100 10000 1Analysis occurs at: 100 1000 10000

PRL X 1 1000 2Analysis occurs at: 1 3 10 30 100 300 1000

PRL BIASV 6 600 3Analysis occurs at: 6 12 30 60 120 300 600

The variable specified must be a tuned value, ideally fromthe equate block.

PRM

Specifies a parameter sweep range and number of points.

Format:PRM variable start-value stop-value number-of-points

TIP: When the end points of a sweep are included, anextra point is required for rational number step sizes.For example, sweeping from 100 to 150 by steps of 10requires six points. The six points are 100, 110, 120, 130,140 and 150.

For example,

PRM C 100 150 10

sweeps “C” from 100 to 150 with 6 points (every 10).

Window Blocks 39

MARKER SUB-BLOCK

The MARKER sub-block is used to specify at what fre-quency/parameter sweep value markers will be displayed.The format is:

MARKERpos1 pos2 pos3 pos4 pos5 pos6 pos7 pos8

If you manually move markers into position, then markersub-blocks can be written automatically by =SuperStar=by using the Save Marker Blocks item from the Utilitiesmenu.

OPTIMIZE AND YIELD SUB-BLOCKS

The OPT and YIELD blocks are described in Chapters 6and 9 respectively.

POST PROCESSING

=SuperStar= can perform simple arithmetic operations(+,-,*,/) on output parameters before displaying them.Post processing is especially useful for optimizing twonetworks to be equal or for a specific difference in perform-ance, such as a 90 degree phase shift. To use post process-ing, the network specifcation (described earlier in thischapter) is replaced with a post processing request. Theformat is (no spaces should be used):

Network Operator Network

where Network is a simple network specification and Op-erator is either +, -, * or /. The operator is a simple realoperator (not complex) that operates on each real quantityindividually. If a difference is taken and S21 is shown indB/angle form, then what is really shown is the differenceof both networks’ DB[S21] and ANG[S21]. If the firstnetwork has S21=15dB∠68° and the second network hasS21=12dB∠62°, then plotting the difference (-) will giveS21=3dB∠6°.

40 Window Blocks

A complete window block using post processing might be:

WINDOWTRANSMODEL(50)-DATA(50)DSP SPARFREQSWP 10 50 5OPT10 50 S11=0 S21=0 S12=0 S22=010 50 ANG[S11]=0 ANG[S21]=0 ANG[S12]=0ANG[S22]=0

This window block optimizes TRANSMODEL(50) andDATA(50) to be equal.

See example 6 for a complete post-processing example.

COMPLEX TERMINATIONS

=SuperStar= can analyze circuits which use complex im-pedances for terminations. This allows analyzing a struc-ture not terminated in a pure resistance (like 50 or 75ohm). One common application is the termination of acircuit into an antenna; another is termination into a highpower transistor. To terminate a circuit with a compleximpedance, a one-port data file must first be created withthe impedance vs. frequency data. A typical file might be:

# MHZ Z RI R 1 ‘Rectangular, unnormalized Z parameters14.00 31.6 -6.614.05 32.0 4.714.10 32.4 16.014.15 32.7 27.214.20 33.1 38.414.25 33.5 49.514.30 33.9 60.714.35 34.3 71.7

This file contains Z parameter data, but a one-port S or Yparameter data file could also be used. See Chapter 5,Device Data, for more information on data files.

Window Blocks 41

To use a file as a termination, simply place the filenamein the Network Specification where the impedance wouldnormally go. Some examples:

MATCH(50,ANTENNA.RX) ‘Terminate with 50 at input, and‘ANTENNA.RX at output

COMBINER(ANT1.RX,ANT2.RX,50)‘Terminate the combiner with‘ANT1.RX at port 1, ANT2.RX‘at port 2, and 50 ohms at port 3.

Use care not to accidentally do the following:

FILTER(ANTENNA.RX) ‘PROBABLY NOT WHAT WAS‘INTENDED!

This most likely incorrect line specifies to terminate allports (input and output) with the same ANTENNA.RXfile.

See example 18 for a complete example using complexterminations.

CIRCLES

Noise, gain, and stability circles can be plotted on either aSmith or a polar chart. Parameters for circles are:

SB1 Input plane stability circles

SB2 Output plane stability circles

NCI Noise circles

GA Available gain circles

GP Power gain circles

GU1 Unilateral gain circles at input

GU2 Unilateral gain circles at output

All circles can be used only with two-port networks.

Stability circles are shown at the marker frequencies.Filled areas are unstable regions.

42 Window Blocks

Noise circles start at Γopt and show loci of constant noise.These circles are at .25, .5, 1, 1.5, 2, 2.5, 3, and 6 dB lessthan optimal noise figure.

Gain circles show loci of constant gain. These circles areat 0, 1, 2, 3, 4, 5, and 6 dB less than optimal gain. Note:With available gain and power gain circles, if K<1, thenthe 0dB (GMAX) circle has a non-zero radius, and theinside of this circle is shaded as an unstable region.

NETWORK SPECIFICATION OVERRIDES

Anywhere that an output parameter is requested (such asS21), a network specification override may be included.The format is:

Network:Parameter

An override can be used in any of the sub-blocks but ismost useful for putting parameters from different net-works on the same graph. This window block is a simpleexample of overrides:

WINDOWLOWPASS(50)GPH S21 ‘Graph S21 of LOWPASS(50)GPH HIGHPASS(50):S21 ‘Graph S21 of HIGHPASS(50)SMH S11 ‘Graph S11 of LOWPASS(50)SMH HIGHPASS(50):S11 ‘Graph S11 of HIGHPASS(50)FREQSWP 0 100 101

See example 6 for a complete example which uses networkspecification overrides.

OUTPUT PARAMETERS

=SuperStar= supports a rich set of output parameters.Starting with Version 6.0, all parameters can be used forany purpose, including graphing, tabular display, optimi-zation, yield, and post-processing. Table 4-2 shows the

Window Blocks 43

available output parameters. Where i and j are shown inthe chart,port numbers can be substituted. Some parame-ters (such as Aii) use only one port, e.g., A11 or V22.

All output parameters have default formats. For instance,using DSP S21 Z32 will display S21 in dB/angle form andZ32 in rectangular (real & complex) form. Likewise, GPH

Parm Description Default Format POL SMH

Sij S parameters DBANG ü ü

Hij H parameters (2-port only) DBANG ü

Yij Y parameters RECT ü

Zij Z parameters (2-port only) RECT ü

Iii Impedance at port i RECT ü Sii

Aii Admittance at port i RECT ü Sii

Vii VSWR at port i Linear (Real) Sii

Eij Voltage gain from ports i to j. DBANG ü

GMAX Maximum available gain dB (Real)

NF Noise figure dB (Real)

NMEAS Noise measure Linear (Real)

NFT Effective noise input temperature Linear (Real)

GOPT Optimal gamma for noise DBANG ü ü

YOPT Optimal admittance for noise RECT ü GOPT

ZOPT Optimal impedance for noise RECT ü GOPT

RN Normalized noise resistance Linear (Real)

NFMIN Minimum noise figure dB (Real)

ZMiSimultaneous match impedance at port i(i=1 or 2)

RECT ü GMi

YMiSimultaneous match admittance at port i(i=1 or 2)

RECT ü GMi

GMiSimultaneous match admittance at port i(i=1 or 2)

DBANG ü ü

KST Stability factor Linear (Real)

B1 Stability measure Linear (Real)

SBi Stability circle at port i (i=1 or 2) Circle ü ü

NCI Constant noise circles Circle ü ü

GA Available gain circles Circle ü ü

GP Power gain circles Circle ü ü

GUi Unilateral gain circles at port i (i=1 or 2) Circle ü ü

Table 4-2 Available =SuperStar= output parameters.

44 Window Blocks

S21 graphs S21 in dB, while GPH Z32 graphs the realpart of Z32.

Output parameters can be combined with operators tochange the data format. The general format for combiningoperators with parameters is:

operator[parameter]

where operator is one of the operators listed in Table 4-3and parameter is one of the parameters listed in Table 4-2.(Parameter can also be one of the DSP types,such as SPAR,listed earlier in the chapter). Note that not all operatorscan be used with all parameters. The “Parm Type” columnin Table 4-3 indicates which type of parameter each opera-tor can use. For example, ANG[] (Angle) cannot be usedwith a real-valued parameter, such as GMAX, soANG[GMAX] is not allowed. Some possible output blocklines are:

Operator Description Parm Type Result Type

MAGANG[ ] Linear magnitude & angle Complex Complex

DBANG[ ] dB magnitude & angle Complex Complex

RECT[ ] Rectangular (real & imag) Complex Complex

MAG[ ] Linear magnitude Real/Complex Real

ANG[ ] Angle Complex Real

RE[ ] Real part Complex Real

IM[ ] Imaginary part Complex Real

DB[ ] dB magnitude Real/Complex Real

GD[ ] Group delay Complex Real

QL[ ] Loaded Q Complex Real

RAD[ ] Radius of main circle Circle Real

PAR[ ]Stable region (-1=stable inside,+1=stable outside)

Circle Real

Table 4-3 Output parameter operators

Window Blocks 45

GPH S22 ‘Graph dB magnitude of S22GPH QL[S21] ‘Graph loaded Q of S21GPH MAG[S21] ‘Graph linear magnitude of S21

POL IM[I11] ‘Graph S11 while showing input admittance‘in the marker text.

DSP RECT[SPAR] ‘Show all s-parameters in‘rectangular form.

DSP RAD[SB1] GD[S21] ‘Display radius of input plane‘stability circles and group delay

DSP NCI ‘Display noise circle data (27 numbers per‘frequency!)

UNITS

The units used in =SuperStar= are

Resistance ohmsInductance nanohenriesCapacitance picofaradsConductance mhosFrequency megahertzDelay nanosecondsLength (elec) degreesLength (phys) mils or millimeters

46 Window Blocks

Chapter 5

Device Data

W ithin =SuperStar= are a wide range of elementmodels. Also, the model and equation features of=SuperStar= Professional provide for user creation

of models. However, it is often necessary or desirable tocharacterize a device used in =SuperStar= by measuredor externally computed data. This function is provided forby the use of the ONE, TWO, THR, FOU, and NPO codeswhich read S, Y, G, H, or Z-parameter data.

Because =SuperStar= is a linear simulator, and becausecircuits are assumed time-invariant (element values arenot a function of time), sub-components are uniquely de-fined by a set of port parameter sets, such as two-portS-parameter data.

Although TWO,THR, FOU,and NPO are typically used foractive devices, they may be used for any devices for whichyou can compute or measure data. For example, they couldbe used to characterize an antenna,a circuit with specifiedgroup delay data, or measured data for a broadband trans-former or a pad.

PROVIDED DEVICE DATA

=SuperStar= includes over 3,400 data files for many dif-ferent device types. Table 5-1 is a list of the representedmanufacturers and device families. Device data was pro-vided by the manufacturers in electronic format.

Eagleware could not test every file that was provided.Through random sampling, we edited errors found insome files. It is the user’s responsibility to test each filefor accuracy.

CREATING NEW DATA FILES

You may easily add other devices to the library using theeditor in =SuperStar= to simply type the data into a filewith the name of your choice. From the =SuperStar=Menu, select File/New and choose Text. Type in the data,and when you have finished, select File/Save. The fileformat is standard ASCII.

Mfg Type No.Alpha FET 11

Pin 72Schottky 54Varactor 106

CoilCraft Inductors 123

Fujitsu All 60

HP Bipolar 77GaAs FET 68GaAs IC 26MSA INA 78Old Avantek 38Old HP 78Si IC 5

MiniCircuits All 15

Mitsubishi MGF1xxx 7

Motorola 2Nxxxx 24FET 10GaAs FET 8LTxxxx 14Misc 36MMxxxx 6MPSxxxx 25MRF5xx 134MRF9xx 118MRFxxxx 9

Mfg Type No.Surface Mount 192

NEC GaAs MMIC 3GaAs Power 65GaAs Sm. Signal 108Si MMIC 37Si Power 4Si Small Signal 585

Philips SOT103 71SOT143 176SOT172 18SOT173 58SOT223 64SOT23 196SOT37 89SOT54 20SOT89 20

Polyfet All 81

Siemens All 388

Stanford SHF 20Microdevices SNA 43

SPF 4

Toshiba S8xxx 8

Total 3,452

Table 5-1 List of manufacturers providing S-Parameter data.

48 Device Data

The first line in the file after any initial comments is aformat specifier in the form:

# units type format R impedance

where:

units is either Hz, kHz, MHz, or GHz

type is the type of the data file, either S, Y, G, H, or Z

format is DB for dB/angle data, MA for linear magnitude/angledata, or RI for real/imaginary data

impedance is the reference impedance in ohms, commonly50 or 75

One of the most common format specifiers is:

# MHZ S MA R 50

This indicates that the data is in S parameter form nor-malized to 50 ohms. The data is given in linear polarformat (magnitude & angle). The frequencies are in mega-hertz.

The data follows after the format specifier. A typical linefor this two-port file is:

500 .64 -23 12.5 98 .03 70 .8 -37

In this case, 500 is the frequency in megahertz. Themagnitudes of S11, S21, S12 and S22 are .64, 12.5, .03 and.8, respectively. The phases are -23, 98, 70 and -37 degrees,respectively.

Alternatively, Y-parameter data may be used. The formatspecifier could be:

# GHZ Y RI R 1

This would indicate rectangular, unnormalized Y parame-ter data with frequencies in GHz. A typical line is:

30 0 3E-4 9E-3 -8E-3 2E-5 0 -1E-4 1E-3

Device Data 49

In this case, the frequency in gigahertz is 30. The realvalues of Y11, Y21, Y12 and Y22 are 0, 9E-3, 2E-5 and -1E-4mhos, respectively. The imaginary values are 3E-4, -8E-3,0 and 1E-3 mhos, respectively.

A sample S-parameter data file is given in Table 5-2. Theonly portion of the file required for =SuperStar= analysisis the segment in the middle with frequencies and S-pa-rameter data. Lines in the data file beginning with “!” arecomments and are ignored. The noise data at the end ofthe file is used for noise figure analysis. (Noise is dis-cussed at the end of this chapter).

FILE RECORD KEEPING

Most device files provided with =SuperStar= are S-pa-rameter files in the usual device configuration, typically

! AT41435 S AND NOISE PARAMETERS! Vce=8V Ic=10mA! LAST UPDATED 06-1-89# GHZ S MA R 50!FREQ S11 S21 S12 S22!GHZ MAG ANG MAG ANG MAG ANG MAG ANG0.1 .80 -32 24.99 157 .011 82 .93 -120.5 .50 -110 1 2.30 108 .033 52 .61 -281.0 .40 -152 6.73 85 .049 56 .51 -301.5 .38 176 4.63 71 .063 59 .48 -322.0 .39 166 3.54 60 .080 58 .46 -372.5 .41 156 2.91 53 .095 61 44 -403.0 .44 145 2.47 43 .115 61 .43 -483.5 .46 137 2.15 33 .133 58 .43 -584.0 .46 127 1.91 23 .153 53 .45 -684.5 .47 116 1.72 13 .178 50 .46 -755.0 .49 104 1.58 3 .201 47 .48 -826.0 .59 81 1.34 -17 .247 36 .43 -101!FREQ Fopt GAMMA OPT!GHZ dB MAG ANG RN/Zo0.1 1.2 .12 3 0.170.5 1.2 .10 14 0.171.0 1.3 .05 28 0.172.0 1.7 .30 -154 0.164.0 3.0 .54 -118 0.35

Table 5-2 Typical S-parameter data file for a bipolar transistor.This file also includes noise data.

50 Device Data

common emitter or common source. Devices you add tothe library may use the ground terminal of your choice.However, if you always keep data in a consistent format,record keeping chores are greatly minimized.

USING A DATA FILE IN =SUPERSTAR=

Data is read into =SuperStar= using the ONE,TWO,THR,FOU, or NPO code in a circuit file. The format of thesecodes is:

ONE n1 n2 Filename=TWO n1 n2 n3 Filename=THR n1 n2 n3 n4 Filename=FOU n1 n2 n3 n4 n5 Filename=NPOx n1... n(x+1) Filename=

(where x is the number of ports)

A typical line is:

TWO 3 4 5 Filename=MRF901.615

Table 5-3 shows a circuit file which uses a two port datafile (NE02135A.S2P). Two-port data is read from a fileand assigned to a location specified by the nodes. For

CIRCUITTWO 0 1 2 F=NE02135A.S2P ‘Q1MUI 3 2 0 1 L1=4.5 L2=75 K=.99 ‘X1MUI 0 1 4 0 L1=75 L2=32 K=.99 ‘X2CAP 5 0 C=0.24 ‘C2CAP 4 5 C=7.5 ‘C1DEF2P 3 5 LOWNOISEWINDOWLOWNOISE(50)GPH S21 0 10GPH NFD 0 5SMH S11SMH S22FREQSWP 500 1000 26OPT500 1000 S21=7 NFD<1.5 S11<-16 S22<-16

Table 5-3 Broadband low-noise amplifier circuit file

Device Data 51

information on how to connect the nodes, see Chapter 12,Reference.

Filename specifies the name of the ASCII file which con-tains the data. The filename may be preceded with apathname.

EXPORTING FILES

“Write S-Data” in the File menu writes S-parameter datafor the network just analyzed to an output data file. Thisoutput data file has exactly the same format as S-parame-ter files used to import data. This allows the user toanalyze, tune and optimize sub-networks which are thenstored as S-parameter data files for use later in othercircuit files. The S-parameter data file written by =Super-Star= has one line of data for each sweep frequency speci-fied in the FREQ block. If there are two or more responsesspecified in the circuit file, =SuperStar= displays a dialogbox to allow you to select the response to use. Select aresponse and type in the desired name. To avoid confusion,we recommend you use the .OUT extension for naming allyour output data files.

NOISE DATA IN DATA FILES

Some of the data files provided with =SuperStar= alsoinclude noise data used for noise figure analysis. This dataincludes the optimum noise figure, NFopt, the complexsource impedance to present to the device to achieve theoptimum noise figure, Gopt, and the effective noise resis-tance, Rn. Example data can be seen in the data filepreviously shown in Table 5-2.

The best noise figure in a circuit is achieved when thedevice is presented with an optimum source impedance.The optimum input network to achieve this objective doesnot in general result in an excellent return loss match.

52 Device Data

Balanced amplifiers and isolators are sometimes used toachieve both the optimum noise figure and a good match.

Losses in the input network, feedback networks aroundthe transistor, emitter feedback and multiple stages alleffect the noise figure of the circuit. All of these effects areaccurately simulated in =SuperStar= using the noise cor-relation matrix technique [5,6]. This capability does notexist in many popular, expensive, simulators.

Device Data 53

Chapter 6

Optimization

One of the joys of mathematics is finding a solution toa difficult problem via expressions. But we are en-gineers; the theory, no matter how elegant, is only a

start. Practical problems such as standard values andcomponent parasitics may preclude a purely theoreticalsolution. When only a few variables in a circuit requireadjustment, =SuperStar= tuning is an effective tool. Asthe number of variables increases, visualization of themultidimensional variable space is difficult, and tuningbecomes less effective. In this event, optimization is thepreferred tool for dealing with practical problems. A cir-cuit optimization is not “run”, but rather “played”. Opti-mization is often a compromise of conflicting requirementswith no exact solution. Effective use of optimization con-sists of an attempt, evaluation of the results, and retries.

=SuperStar= includes two distinctly different optimiza-tion algorithms; a gradient search and a pattern searchwith adaptive and independent step size for each variable.Eagleware Corporation considers these routines proprie-tary. However, they are described here in sufficient detailfor effective use of the optimizer. Also, it cannot be over-emphasized that a major factor contributing to the effec-tiveness of =SuperStar= optimization is its unmatchedexecution speed.

The gradient optimizer is very effective in the early phaseof an optimization effort. It is reasonably tolerant even of

poor initial component values and a large number ofcomponents. It often makes significant progress after onlya few rounds. However, gradient search algorithm pro-gress tends to halt before achieving optimum final values.

The =SuperStar= pattern search is effective in the finalphases of an effort. It is based on an optimizer describedin the paper, “The Effectiveness of Four Direct SearchOptimization Algorithms”, Randall W. Rhea, IEEE 1987MTT-S International Microwave Symposium Digest, June9, 1987. The current routine improves the previous rou-tine because 1) adaptive and independent variable stepsize was introduced and 2) fewer evaluations of the circuitare required for a given number of steps of the variables.The pattern search algorithm is very resistant to “hang.”

=SuperStar= contains an automatic mode which initiallyinvokes the gradient optimizer. When progress halts asevidenced by a suspension in the decline of the error fromtarget (objective function), the pattern search algorithm isinvoked. A fixed number of pattern searches is appliedand then the gradient optimizer is again invoked. Theuser begins this automatic optimization mode by selecting“Automatic” from the Optimize menu.

OBJECTIVE FUNCTION

Each set of component values results in an error from thedesired response. The error computed by =SuperStar= isthe root mean square of individual parameter error terms.The error per frequency is given by

where

p = error function power (always 2 or 6)Tn = Set of target values

E T V Wn n

p

nn

= −∑ b ge j

56 Optimization

An = Set of actual valuesWn = Set of target weights

The exponent “p” is always even, therefore the magnitudeof each error contribution is always positive. When theuser selects pattern search, p=2, which results in a root-mean-squared error minimization. When the user selectsgradient or automatic optimization, p=6, which tends to aChebyshev error minimization.

Each line in an OPT block adds to the error value asdetermined by the above equation. The total error valueis the sum of the errors per frequency divided by thenumber of frequencies, these added for each OPT blockline. A specified parameter has a default weight of 1unless modified by the weight option.

The optimization routine attempts to reduce the totalerror value by adjusting the values of all components inthe circuit file or schematic marked with a “?”.

The error and number of rounds are displayed during theoptimization process. A “P” suffix on the number of roundssignifies the pattern search is currently active while a “G”indicates gradient optimization is active.

Each round evaluates all marked components.

If the user selects gradient optimization or the automaticmode from the menu or the automatic mode by pressingF3, optimization begins immediately. Optimization con-tinues until interrupted by pressing Esc or until the errorreaches zero. Optimization may be interrupted and re-started at will. Manual tuning may be applied during theinterruption.

If the user selects pattern search optimization, the vari-able step size is prompted and optimization begins. Forbroadband circuits, a moderate step size such as 5% isreasonable. For narrow-band circuits a smaller initial

Optimization 57

step size is recommended. Because the step size is ad-justed dynamically during optimization, the initial stepsize is not critical.

After optimization has run a while, variable step sizesnormally decrease. If optimization is interrupted tomanually adjust variables, it is good practice to specify asmaller step size when restarting optimization.

If too large an initial step size is chosen, the early roundsof optimization do not modify the circuit values; they areused to reduce the variable step sizes. On occasion, theerror value may actually increase. This attribute of =Su-perStar= optimization allows it to “wander” in search of abetter ultimate solution. If this happens at the beginningof a run, it may be indicative of too large an initial stepsize.

A powerful feature of =SuperStar= is the ability to observeresults, interrupt the run and manually tune one or morevariables, and restart the optimization process. This addsconsiderable power and flexibility to the routine.

THE OPT BLOCK

A line in the OPT block might be

10 70 S21>-1

Each line in the OPT block begins with two numbers whichindicate the frequency range that applies to the conditionsof that line. In this example, the forward gain, S21, is tobe greater than -1 dB over the frequency range of 10 MHzto 70 MHz.

This OPT line is very simple. Each line may specify oneor more of the output parameters shown in chapter 4. Themaximum number of lines in an OPT block is limited onlyby available memory. The allowed operators are =, >, <and %. The = operator attempts to optimize to the speci-

58 Optimization

fied value. < or > attempt to optimize a parameter to beless than or greater than the specified value. The %operator attempts to flatten the specified parameter with-out regard for a specific value.

This three line optimization block for a bandpass filter

10 40 S21<-4055 85 S21>-1 GD[S21]%100 130 S21<-40

attempts to achieve at least 40 dB of rejection in lower andupper stopbands and less than 1 dB insertion loss with flatdelay in the passband.

This one line optimization block for an amplifier

2000 4000 S21>11.5 S21<12.5 S11<-10 S22<-10

attempts to achieve better than 10 dB of return loss in anamplifier with 11.5 to 12.5 dB of gain. A similar optimi-zation block would be

2000 4000 S21=12 S11<-10 S22<-10

OPTIMIZATION EXAMPLE

For further insight on how to use optimization, considerthe following examples. They are variations on a 50 to 950MHz amplifier. The schematic is given in Figure 6-1 andthe circuit file in Table 6-1.

The OPT block specifies a 12 dB gain target for theamplifier. No other parameters are specified for optimiza-tion, but the input and output return loss are displayed.

The frequency range of optimization in this example is 50to 950 MHz. The frequency range for displaying resultscan be wider than the optimization range, if desired.

Optimization 59

TIP: To reduce optimization time, specify a minimumnumber of frequency points.

Broadband circuits typically do not require many samplefrequencies. The output results can be somewhat rough.After optimization, the number of frequency points can beincreased to obtain smoother curves for documentation.In the present example, there are 10 points. Were it notfor the end L-C matching networks,even fewer frequenciescould have been chosen.

1

0

2

3 4

2

4

5

0

4

0

6

AMP

C1

?2 pF

L1

?2 nH

R1

?390 ohm

L2

?24 nH

Q1

R2

?6.8 ohm

C2

?3 pF

L3

?10 nH

Figure 6-1 Broadband UHF amplifier optimization example

CIRCUITCAP 1 0 C=?2 ‘C1IND 1 3 L=?2 ‘L1RES 3 4 R=?390 ‘R1IND 4 5 L=?24 ‘L2TWO 3 5 11 F=MRF901.615 ‘Q1RES 11 0 R=?6.8 ‘R2CAP 5 0 C=?3 ‘C2IND 5 9 L=?10 ‘L3DEF2P 1 9 AMP

WINDOW AMP(50)GPH S21 0 20GPH S11 -20 0GPH S22 -20 0FREQSWD 50 950 100OPT50 950 S21=12

Table 6-1 Amplifier optimization example file SS4T61.CKT

60 Optimization

CAUTION: It is very important that the frequencies atwhich the circuit is optimized are also frequencies cho-sen by the FREQ block.

For example, if a line in the OPT block specifies a fre-quency range of 55 to 59 MHz for a parameter target, butthe analysis frequencies are 0 to 100 MHz in 10 MHz steps,the optimizer will not “see” the target in the 55 to 59 MHzrange.

Selective devices, such as filters, should have at least a fewpoints in the pass and stopbands. Corner frequenciesshould be represented. Group delay optimization requiresmany frequency points and is slower.

Now for the results. Run =SuperStar=, read the fileSS4T61.CKT, and begin optimization by selecting “Auto-matic” from the Optimize menu. The gain flatness im-proves quickly and then slowly continues to improve.After many rounds you should see the results in Figure6-2. Stop the optimization by pressing Esc.

The gain flatness is greatly improved and the gain is nearthe 12 dB target. However, the return loss is worse.

To improve the return loss, edit the OPT block to

OPT50 950 S21=12 S11<-18 S22<-18

In general, the > and < operators are preferred over the =operator. If the condition of one parameter is satisfied,=SuperStar= can “concentrate” on satisfying other pa-rameters. The = operator is almost never satisfied, onlyapproached.

Exit the editor and begin optimization again by selecting“Automatic” from the Optimize menu. After a few roundsthe gain is reasonably flat and the worse case input and

Optimization 61

output return losses are -16.7 dB. Results are shown inFigure 6-3.

We have improved the return loss. However, the gain isnow only about 11dB. =SuperStar= made the tradeoff tosacrifice some gain to improve return loss. Suppose thegain is more important. Change the OPT block to

OPT50 950 S21=12@10 S11<-18 S22<-18

A new technique is tried here. The weight of S21 (thenumber 10 after the @ symbol) is increased from thedefault value of 1 to 10 in an attempt to force =SuperStar=to improve the gain (S21).

Figure 6-2 First attempt at optimization. Gain flatness isexcellent but the return loss is worse.

62 Optimization

Run the optimization with this new OPT block. The returnloss is sacrificed somewhat (worse case -14.7 dB insteadof -16.7 dB), but the gain flatness is markedly improved.

Further improvement in the return loss, and recoveringthe lost gain, would require a more complex circuit or abetter transistor. Replacing the MRF901.615 with a tran-sistor with a higher S21 at 950 MHz can give improvedresults. For example, if an LT4785.825 is used, the targetsof the last OPT block above are completely satisfied andthe optimization terminates. In that case, the gain win-dow could be tightened.

OPTIMIZATION WEIGHTS

In the previous optimization example,weights were addedto increase the emphasis on improving the input and

Figure 6-3 Second optimization attempt with improved returnloss.

Optimization 63

output return losses. Any optimization parameters mayinclude weights. When a parameter is specified on a line,the weight defaults to 1. This default is overridden byadding an @ symbol to the optimization target followed bya weight factor. Use a weight factor greater than one (suchas 10) to make the target more important. Use a weightfactor between zero and one (such as 0.1) to make thetarget less important.

For many optimizations, weight factors are unnecessary.This is often the case when the specified parameters aresimilar in value. Use of < and > operators instead of = alsoreduces the need for weights. When the error resultingfrom a parameter is zero because the condition is satisfied,the weight multiplier has no effect.

When the optimized parameters represent a wide rangeof values, weights are used to obtain a more desirablesolution. Remember, optimization is a search for a com-promise. Weights are not used to obtain a “correct” solu-tion, but rather to “sculpt” a solution more desirable to theuser. This is why we say optimization is not run butplayed. The user observes the optimization results andthen modifies the parameter targets and weights to obtaina “better” solution.

For more optimization examples and tips, see Chapter 11,Examples.

64 Optimization

Chapter 7

Equations

T he =SuperStar= simulator includes the ability todefine component values by algebraic equations.These equations are contained in the EQUATE block

in the circuit file. The EQUATE block provides a rich setof mathematical functions, operators and control state-ments with automatic parsing. This language within thecircuit file significantly enhances the power and flexibilityof circuit simulation. It provides for simple features suchas gang-tuning and more complex features such as user-created functions.

This chapter first gives a few examples of circuits whichuse the EQUATE block. A reference section containingdescriptions of all EQUATE block functions follows theexamples.

New in 6.0: Function definitions and inline equations.

BANDPASS FILTER WITH EQUATIONS

The circuit shown in Figure 7-1 is a top-C coupled band-pass filter. Normally the user computes filter componentvalues manually or with =FILTER=, and these constantvalues are used in the =SuperStar= circuit file. In theEQUATE block, equations which define the inductor andcapacitor values can be embedded right into the circuit file.The EQUATE block computes filter component valuesfrom other variables such as the filter center frequency

and bandwidth. An example =SuperStar= circuit file isgiven in Table 7-1.

In the CIRCUIT block, the component values for the in-ductors and capacitors are replaced by variable namessuch as C12 which are defined in the EQUATE block. TheOUTPUT and FREQ blocks are unchanged.

The first line in the EQUATE block must be the wordEQUATE by itself on a line. The second line in thisexample assigns the value of 100 to the variable Fo. Thisvariable represents the center frequency in MHz. The

Figure 7-1 Top-C coupled bandpass filter.

CIRCUITPLC 1 0 L C1 QL 1000CAP 1 2 C12PLC 2 0 L C2 QL 1000CAP 2 3 C23PLC 3 0 L C3 QL 1000CAP 3 4 C23PLC 4 0 L C2 QL 1000CAP 4 5 C12PLC 5 0 L C1 QL 1000DEF2P 1 5 AUTOFILTWINDOWAUTOFILT(50)GPH S21 -50 0GPH S21 -50 0GPH DLY 0 250FREQSWP 75 125 201EQUATE

Fo=?100BW=?25QL=?120Qbp=Fo*1E6/(BW*1E6)Q1=1.301*QbpQN=Q1K12=.703/QbpK23=.536/QbpL=50/(2*PI*Fo*1E6*Q1)Cnode=1E12/(Fo^2*1E12*39.48*L)L=1E9*LC12=K12*CnodeC23=K23*Cnode

C1=(Cnode-C12)C2=(Cnode-C12-C23)C3=(Cnode-C23-C23)

Table 7-1 Circuit netlist for the Top-C coupled bandpass filter.

66 Equations

question mark following the equal sign tells =SuperStar=that this value can be tuned, optimized and analyzed inMonte Carlo in the same way as a value in the CIRCUITblock.

The only format allowed for tune, optimization, and MonteCarlo values in the EQUATE block is

Variable_Name = ?Value

A value within an expression cannot be tuned, so thestatement

VAR=2*?3

is NOT legal, and generates an error message. To get thedesired result, use two lines

A=?3VAR = 2 * A

The next two lines assign 25 MHz to the bandwidth and120 to the unloaded Q of the inductors. The remaininglines in the EQUATE block compute component values forthis fifth order 0.25 dB ripple Chebyshev bandpass filterwith 50 ohm termination. Q1, QN, K12 and K23 define theChebyshev response.

This is an unusual EQUATE block example which pro-vides insight into the behavior of this popular UHF band-pass filter. To experiment with this example, from the=SuperStar= File menu select Open *.CKT (Text) File andselect the file SS4T71.CKT. The amplitude transmissionand group delay responses should appear on screen.

USING EQUATIONS IN A SCHEMATIC

To use equations in a schematic, you must type theEQUATE block into the text portion of the schematic. Itshould be the first block in the text. Next, place thesymbols on the schematic. When entering the values into

Equations 67

the symbol’s dialog box, type a variable name or formulain place of a part value.

VIEWING VARIABLE VALUES

Values calculated in the EQUATE block may be viewed toverify that the equations yield expected results. From theWindows menu, select “Open View-Variables”. Yourscreen should look similar to Figure 7-2.

FUNCTION DEFINITIONS

Functions can be created in =SuperStar=. Their format is:

FUNCTION name(parm1,parm2...)equationsRETURN expression

Figure 7-2 Top-C coupled bandpass filter simulation.

68 Equations

Functions take zero or more parameters as input andreturn exactly one value as output. All variables usedwithin a function are local; that is, variables cannot beshared across functions or with the main equate block. Anexample function to calculate the inductance that reso-nates with a capacitor at a given frequency:

FUNCTION RESL(C,F) ‘L is in nH, C is in pF, F is in MHzFHz=1e6*FCFarads=1e-12*COmega=2*PI*FHzLHenries=1/(Omega*Omega*CFarads)Return LHenries*1e9

Functions should go in the text portion of the file beforeany window blocks. Here is a circuit file which uses thisfunction:

CIRCUITCAP 1 2 C=C1IND 2 3 L=L1CAP 3 0 C=C2IND 3 0 L=RESL(C2,100)CAP 3 4 C=C1IND 4 5 L=L1DEF2P TEST 1 5EQUATEC1=?10L1=RESL(C1,100)C2=?5WINDOWTEST(50)GPH S21FREQSWP 0 1000 101

If you have functions you want to save permanently, placethem in a text file with the extension .FUN (such asRESL.FUN) and put that file in the \EAGLE\MODELdirectory. (Multiple functions can be placed in one file.)The functions are now usable by any circuit file.

Equations 69

EQUATE BLOCK REFERENCE

Each line of the EQUATE block must be in one of sixformats described below. The comment line format is

‘(Comment)

Example

‘This line will be ignored.

A line is considered a comment if the first character in theline is an apostrophe (‘). Any part of a line can be acomment and everything after the apostrophe is ignored.

The assignment line assigns a value to a variable. Theformat is

Variablename = Expression

Examples of an assignment line are

X=2R=4*3/2^4*(9+8)Voltage=(2+R)*Current

The assignment statement calculates the value of theexpression and then gives the value to the specified vari-able.

A tune statement assigns a value to a variable and allowsthat variable to be tuned, optimized, or included in theMonte Carlo analysis. The tune statement format is

Variablename = ?Value

Examples

X=?2Large_R=?3.54e+16

The tune statement must be a single assignment, not anexpression. Therefore, the following statement is illegal

X=?2+2

70 Equations

The label statement identifies a section of the equationblock. The format is

LABEL Labelname

This statement sets a LABEL for use in GOTO or IFTHENGOTO statements. After the GOTO is executed, the state-ment following LABEL is the next statement executed. IfLABEL is the last statement in the EQUATE block, theEQUATE block ends after the GOTO.

The format of the GOTO statement is

GOTO Labelname

This statement causes the EQUATION interpreter tojump in its calculations to the statement following thecorresponding LABEL statement.

The format of the the IF statement is

IF expression THEN statement

This statement is perhaps the most powerful one includedin the =SuperStar= EQUATE interpreter. This statementcauses the following steps to occur.

1) The value of the expression is calculated. Any true compari-son results in a value of -1. For example, the expression 1>0gives a value of -1, while the expression 0>1 gives a value ofzero.

2) The value obtained in step one is compared to zero. If thevalue is not zero, then the interpreter performs the statementspecified.

Example of the use of labels:

IF FREQ>1000 THEN GOTO HIGHFREQRVal = 100GOTO DONELABEL HIGHFREQRVal = 500LABEL DONE

Equations 71

Since =SuperStar= uses approximate calculations (as anycomputer program must), round-off errors are inevitable.To work around this problem, =SuperStar= does not checkfor a value to be exactly equal to zero; rather, the valuemust be within the range ±0.0001. This could cause aproblem if you are using very small values. If this is thecase, change

IF value THEN GOTO LABEL

to

IF ABS(value)<0.0000001 THEN GOTO LABEL

or something similar. If you are using relational operatorssuch as greater than (>) or less than (<), then this pointdoes not need to be considered.

ALGEBRAIC EXPRESSION FORMAT

An algebraic expression in =SuperStar= must have one ofthe following formats:

VALUE [Operator expression]FUNCTION [Operator expression](expression)

A value can be either a number or a variable name. Thefollowing are some legal examples:

1.050.0535.13425e+16XSlope

Variable names must start with a letter. The remainingcharacters may consist of letters, numbers, and under-scores ( _ ).

Operator descriptions in precedence order are

72 Equations

^ Exponentiation: Raises a number to a powerFor example, 2^3 is 8, and 3^2 is 9.

* Multiplication/ Division\ Integer Division: The result obtained is truncated to

an integer result. For example, 10\3 is 3 and3\4 is zero.

% Modulo: The numbers are divided, and the remainderis returned. For example, 10%3 is 1 and 7.6%2 is 1.6.

+ Addition- Subtraction= Equality: left and right values are compared. If the

results are equal, the value is -1 (true); otherwise, thevalue is zero (false). For example, 1+1=2 gives -1and 1+1=3 gives zero.

> Greater than: this operator and the following threerelational operators operate in the same manner asthe equality operator.

< Less than>= or => Greater than or equal<= or =< Less than or equal

The following NOT, AND, OR, Exclusive-OR, EQV andIMP operators are called logical operators. They can beused to combine relational tests, such as “10 & 3". Theycan also be used in binary math; for more details see thesection on LOGICAL Operators.

! NOT& AND| OR: This symbol is also referred to as “pipes”. It is

normally located above the back-slash (\) key.@ Exclusive OR: The result is true if one of the values is

true, but not both. “13 @ 54" is true (-1), but ”10 @54" is false (zero).

# Logical Equivalence (EQV): The result is true if bothvalues are true or both values are false. “1=3 # 5=4"is true, and ”1=1 # 5=4" is false.

$ Logical Implication (IMP): The result is always trueunless the first value is true AND the second value is

Equations 73

false. You may never need this operator; it is includedfor completeness. “1=3 $ 1=1", ”1=3 $ 1=2", and“1=1 $ 2=2" are all true, while ”1=1 $ 2=1" is false.

BUILT IN FUNCTION DEFINITIONS

CAUTION: Standard trigonometric functions must havean argument in degrees, and inverse standardfunctionsreturn values in degrees. NEW IN 6.0: Hyperbolic trigo-nometric functions use pure numbers (not degrees).

SIN(expression) sine of the argumentCOS(expression)cosineTAN(expression) tangent

Range: Argument must not be ±90, ±3*90, etc.ARCSIN(expression) inverse sine

Range: Argument must be between -1 and +1.ARCCOS(expression) inverse cosine

Range: Argument must be between -1 and +1.ARCTAN(expression) inverse tangent

Alternate form: ATN(expression)SINH(expression) hyperbolic sineCOSH(expression) hyperbolic cosineTANH(expression) hyperbolic tangent

Range: Same as TAN(expression)ARCSINH(expression) inverse hyperbolic sineARCCOSH(expression) inverse hyperbolic cosineARCTANH(expression) inverse hyperbolic tangentABS(expression) absolute value of expressionEXP(expression) value of “e” raised to expressionLOG(expression) base 10 logarithmLN(expression) natural logarithmFIX(expression) truncates the expression

Examples: FIX(5.6) is 5 and FIX(-1.4) is -1INT(expression) greatest integer less than or equal

to the expressionExamples: INT(5.6) is 5 and INT(-1.4) is -2

RND returns a pseudo-randomnumber between zero and one

SQR(expression) square root

74 Equations

SPECIAL VALUES

PI π, 3.14159265FREQ current sweep frequency in MHz._EPS0 ε0, 8.854e-12_ETA0 η0, 376.7343_MU0 µ0, 1.256637e-6_VAIR c, 2.997925e8_LN2 ln(2), 0.6931471805599_EXP1 e, 2.718281828459_RTOD Rad to deg multiplier, 180/π_DTOR Deg to rad multiplier, π/180

CAUTION: Using FREQ decreases execution speed be-cause the EQUATE block must be evaluated for everyfrequency. Normally, the calculations in the EQUATEblock are performed once.

SAMPLE EXPRESSIONS

Expression Value1+2*3 7(1+2)*3 94^3 643*4^3 19219/4 4.7519\4 419%4 31+19%2*2^2 55>4 -1 (True)5<4 0 (False)2*4>1+3 & 4*4<17^2 -1 (True)2*4>1+3 @ 4*4<17^2 0 (False)SIN(180)<.5 -1 (True)

LIMITS AND RESTRICTIONS

Number of variables No limitMaximum expression nesting 32Maximum length of variable name (characters) 12Maximum number of GOTO statements No limit

Equations 75

Maximum number of LABEL statements No limitMaximum number of variables in CIRCUIT block 1000Accuracy IEEE double precision

(About twelve digits)

All variable names must start with an alpha character.The rest of the name may contain letters, numbers and theunderscore ( _ ) character.

Variables are not case sensitive, so the following sets ofvariables are the same.

CURRENT and currentVoLtAgE and vOlTaGe

LOGICAL OPERATORS

This section assumes that you are familiar with basicconcepts of binary arithmetic and logical operators.

Whenever a logical operation (such as &, |, and @) isperformed, the values used are first converted to 16-bitsigned integers (truncated). The operation is performed,and then the numbers are converted back to floating pointformat. This causes logical operators to work as expectedwhen combined with relational operators: true is given avalue of -1, which corresponds to all ones in binary nota-tion; false is 0, which corresponds to all zeroes. So, whena logical operation is performed after a relational test, thevalue is either -1 (true) or 0 (false). This is the rationalefor having the IF THEN GOTO Statement branch on anonzero value. Relational operators act as expected onbinary numbers, although there are no facilities includedfor conversion between binary and decimal format. So, thevalue of 5&4 is 4, the value of 128|64 is 192, and the valueof 15 @ 7 is 8. The not operator (!) changes each 0 in thebinary representation to a 1, and changes each 1 to a 0.Here are logical operator truth tables

76 Equations

A B !A A&B A|B A@B A#B A$B

0 0 1 0 0 0 1 10 1 1 0 1 1 0 11 0 0 0 1 1 0 01 1 0 1 1 0 1 1

RESERVED WORDS

Variable names should not use any of the following re-served words.

ABS ARCCOS ARCCOSH ARCSINARCSINH ARCTAN ARCTANH ATNCIRCUIT COS COSH EQUATEEXP FIX FREQ FUNCTIONGOTO IF INIT INTLABEL LIBRARY LN MARKERMEM MODEL OPT PIRETURN RND SETMEM SETVARSIN SINH SQR TANTANH THEN TUNE VARWINDOW YIELD _EPS0 _ETA0_MU0 _VAIR _LN2 _EXP1_RTOD _DTOR

Equations 77

Chapter 8

User Models

User models allow the creation of new elements by theuser. These models behave just as if they were builtinto the simulator. In fact, most of the new models

created in Version 6.0 were created using this capability.

To create a new model, you must know three things:

1. The equivalent circuit of the model.

2. Equations which define the component values inthe equivalent circuit.

3. The parameters which will be specified (if any)each time that the model is used.

USING THE MODEL EDITOR

Note: You must have purchased =SCHEMAX= to use themodel editor. If you have not, you may add a model toa text circuit file using the process described later in thechapter.

To create a model using the built-in model editor, followthese steps:

1. Start =SuperStar=.

2. Select “Start Model Editor” from the Edit menu.You will see a screen very similar to =SCHE-MAX=.

3. Draw the equivalent circuit for the model. This circuitmight be just one schematic object or might be amore complex circuit.If you have equations for S orABCD parameters, you should draw a circuit whichonly has one element (an S or ABCD parameter ele-ment), an input, an output, and a ground.

4. If your model does not use equations to define values,skip to step 7. Otherwise, select “Edit Equations”from the File menu.

5. Enter any equations needed to define component val-ues in the model. These equations can be a functionof the input parameters for the model, but cannotuse variables from another model or a main equateblock.

NOTE: Do not use the word EQUATE in the equation text.It is unnecessary and will cause an error.

6. Press Esc to close the equation editor.

7. Enter values for components (by double-clicking onthem). These values can be numbers, equation vari-ables (see step 5 above), input parameter variables,or inline equations.

8. Select Edit Model Parameters from the File menu.This will bring up a box allowing entry of the pa-rameter names for the model. This box is where pa-rameters that must be given each time the model isused are specified.

9. Press the “Add Parm” button. This will bring up theAdd Model Parameter window.

10. Fill in the three prompts and press OK.

11. Repeat steps 9 and 10 for all model parameters.

12. Press OK to close the Edit Model Parameters window.

80 User Models

13. Select “Save Model As” from the File menu.

14. Press OK to confirm the model parameters.

15. Choose the library and model name. For a newmodel and library, select <New File> and <NewObject>.

Note: All models are stored in model library files. Thesefiles are located in the \EAGLE\MODEL directory andmust have a .MOD extension. The name given to themodel is the name used to refer to the model in a circuitfile. All names in all libraries should be unique.

16. Select Exit Model Editor from the File menu to re-turn to =SuperStar=.

For an example of creating a model, see example 20,USERMODL.SCH, in the Examples chapter.

USING A MODEL IN =SCHEMAX=

You can replace any element with a user defined model in=SCHEMAX=. To do this:

1. Double-click on an existing symbol that you havealready drawn to change its model.

2. Press the Model button.

3. Choose the model to use from the combo box.

4. Press OK.

5. Enter the parameters required for the model andpress OK.

ADDING MODELS TO THE =SCHEMAX= MENUS

The USER1 toolbar in =SCHEMAX= initially contains theVAR example; USER2 and USER3 are initially empty.They can be filled by the user with any built-in or user

User Models 81

defined models. To add a model and an associated pictureto a user toolbar:

1. Start =SuperStar=.

2. Select “New” from the File menu.

3. Press the “Schematic” button. You will now be in=SCHEMAX=.

4. Select “=SCHEMAX= User Toolbars” from the Editmenu.

5. Press the button for the toolbar you want to edit. Thiswill bring up the Edit Toolbar window.

6. Select “Add Button”. This will add a button to the tool-bar.

7. Enter the button name.

8. Enter the help tip text. This is the description that ap-pears when the mouse is over the button.

9. The Change Button entry dialog will now appear. Se-lect the combination of MODEL, picture, and shortpicture for this entry.

10. Press OK.

11. If you want to add additional entries for this button,click “Add Entry” and repeat steps 9 and 10. Thiswill cause a popup menu to appear when the buttonis selected.

12. Press OK when you are done editing the user toolbar.

13. Click on the yellow button with the toolbar you haveedited to open your new toolbar.

82 User Models

TEXT MODEL DEFINITIONS

Note:The preferred method for creating models is to usethe schematic based model editor already described.

If you do not have =SCHEMAX=, you may create a textdescription of your models. The format is as follows:

MODEL name(parm1,parm2,...)[model equation lines]model description linesDEFnP node1 node2...noden name

where

name is the name of the modelparmx are the parameters specified by the usermodel equation lines contain the equations for the modelmodel description lines contain elements which make up the

modeln is the number of external nodes on the modelnodex are the external nodes used in the model description

lines

The text equivalent for the model give in example 20(USERMODL.SCH) is:

MODEL VARACTOR(Vt,Co,Gamma,Lp,Cp,Q)Cv=Co/(1+Vt/0.6)^GammaC4=Co/(1+4/0.7)^GammaRs=1/(3.14168e8*C4*1E-12*Q)CAP 1 2 C=CvRES 2 3 R=RsCAP 1 3 C=CpIND 3 4 L=LpDEF2P 1 4 VARACTOR

This model can be typed or copied into any file which usesthe VARACTOR model. It can then be used as follows:

VARACTOR n1 n2 V=x Co=x G=x Lp=x Cp=x Q=x

User Models 83

Models can also be saved into text files and included withthe LIBRARY statement. For example, the statement

LIBRARY \EAGLE\MYFILES\SIMPLE.MOD

loads all models and functions in \EAGLE\MY-FILES\SIMPLE.MOD. If used, LIBRARY statementsshould be the first statement in the circuit file text.

84 User Models

Chapter 9

Statistical Functions

Experienced RF/microwave engineers know that ca-pacitors are not capacitors and inductors are notinductors. The parasitics associated with a compo-

nent can significantly affect the circuit response. Skilleddesigners include appropriate parasitics in the circuitdescription. Because lumped-component parasitics arestrongly influenced by the implementation, such as com-ponent mounting, expecting the circuit simulator to han-dle all the parasitic issues is unrealistic. The engineerwho studies the components and models his or her circuitcarefully will acheive a level of performance and agree-ment that others don’t even comprehend.

Production oriented design involves an additional step.The effects of component tolerances on responses encoun-tered in the production process is studied to gain confi-dence that the yield will fall within acceptable limits.

One method of gaining confidence is to consider worst casescenarios. The circuit response is computed with eachcomponent stepped up or down in value by the appropriatetolerances. The response is observed while all componentsare stepped in the direction resulting in the worst possibleoutcome for the parameter being considered. This processis fast and insightful with a real-time simulator such as=SuperStar=. However, the outcome is generally pessi-mistic. Redesign, to fit worse case scenarios into desired

specifications, may result in greater cost than rejecting orrepairing a few units which fail test.

Monte Carlo analysis evaluates circuit behavior for asample run size with a random distribution of componentvalues within specified limits. It is a statistical process.It does not tell us with certainty what will happen with aparticular unit, but it gives us confidence that productionresults will fall within acceptable limits.

EXAMPLE MONTE CARLO RUN

Given in Figure 9-1 are two 7th order 0.0432 ripple Che-byshev filters designed in =FILTER= and merged togetherin the =SCHEMAX= file MONTE.SCH. The filter on thetop is a lowpass with a cutoff of 900 MHz and the bottomfilter is a top-C coupled bandpass from 850 to 950 MHz.Given in Table 9-1 is the text portion of the schematic.

LOWPASS(1)

C1

?3.5647 pF

L1

?12.704 nH

C2

?6.8606 pF

L2

?14.341 nH

C3

?6.8606 pF

L3

?12.704 nH

C4

?3.5647 pF

(2)

BANDPASS(1)

C1

?1.1737 pF

L1

?10 nH

C2

?1.8053 pF

C3

?0.29278 pF

L2

?10 nH

C4

?2.6525 pF

C5

?0.21104 pF

L3

?10 nH

C6

?2.7466 pF

C7

?0.19863 pF

L4

?10 nH

C8

?2.759 pF

C9

?0.19863 pF

L5

?10 nH

C10

?2.7466 pF

C11

?0.21104 pF

L6

?10 nH

C12

?2.6525 pF

C13

?0.29278 pF

L7

?10 nH

C14

?1.8053 pF

C15

?1.1737 pF

(2)

Table 9-1 Seventh order 0.0432 dB ripple Chebyshev lowpassfilter (top) and bandpass filter (bottom).

86 Statistical Functions

WINDOWLOWPASS(50,50)GPH S21 -60 0GPH S11 -30 0MARKER1e-06 900 1260 1800 1e-06 540 1260 1800FREQSWP 0 1800 101YIELD0 900 S11<-151620 1800 S21<-40

WINDOWBANDPASS(50,50)GPH S21 -60 0GPH S11 -30 0MARKER850 900 950 1050 750 840 960 1050FREQSWP 750 1050 121

Table 9-2 Text portion of the =SCHEMAX= file MONTE.SCH

Table 9-3 Responses of the 7th order Chebyshev lowpass (left)and 7th order Chebyshev bandpass (right) with nominal element

Statistical Functions 87

The responses with nominal element values is shown inFigure 9-2. The 0.0432 dB passband ripple results inapproximately 20 dB return loss in the passband. Duringsynthesis in =FILTER=, the capacitor Q was set to 600 andthe inductor Q was set to 130 for both filters. Notice thatthe insertion loss due to finite component Q is greater inthe bandpass than the lowpass.

The two filters are merged in =SCHEMAX= by pasting theentire schematic of the bandpass into the schematic writ-ten from =FILTER= for the lowpass. Next, all the partsare selected by drawing a box around them and then fromthe Edit menu, “Add Question Marks to Selected Parts” isselected. This places a question mark with the first valueof every component in the schematic. Question markspreceding component values in the file indicate thosevalues are included in the Monte Carlo analysis.

Next, from the Statistics menu, “Monte Carlo Setup” isselected. Figure 9-3 showns the Monte Carlo Setup win-dow. A component is selected from the list on the left anda distribution and tolerance is entered. Alternatively, allcomponents can be set at a specified distribution andtolerance. Other options are discussed later. In this caseall componentsare left at the de-fault ±5% uni-f o r mdistribution.

Next, from theEdit menu“Monte Carlo” isselected. MonteCarlo paintsmultiple re-sponses on thescreen, each

Table 9-4 Monte Carlo Setup window.


with a psuedo-random set of component values based onthe specified distribution and tolerances. The processcontinues until the specified number of runs (sample size)is achieved. Results are given in Figure 9-4. At the end ofthe run, the markers display response values for thenominal component values.

Even though these filters were designed from the samelowpass prototype and the component tolerance for bothare ±5%, notice that the sensitivity of the bandpass is fargreater than the lowpass. The worst return loss case forthe lowpass is approximately 14 dB while several of thebandpass samples have a return loss of only 3 dB! Suchoutcomes might not be intuitively obvious prior to MonteCarlo analysis. Monte Carlo analysis can be very insight-ful and provides an understanding of circuit behavior andproblem areas.

Figure 9-1 Monte Carlo analysis of the lowpass (left) andbandpass (right) filters.


MONTE CARLO SETUP

To change the Monte Carlo setup, including the samplesize or component distributions, from the Statistics menuselect “Setup Monte Carlo”. The window shown in Figure9-3 appears. Given below are descriptions of options avail-able in this window.

VARIABLES: This list includes each component variablein the schematic or text net list which includes a questionmark. You may select a particular variable and then selecta distribution type and enter %Up and %Down tolerancesfor that component. Alternatively, you may select a distri-bution type and enter %Up and %Down tolerances andMake All the Same.

DISTRIBUTION: Two component distribution forms aresupported. With a uniform distribution, components areadjusted above and below nominal, with equal prob-abilities for any value.

A normal distribution results when a large number ofindependent events produce additive effects. The distri-bution curve is bell shaped around the nominal value. Thesum of several tossed dice follows a normal distributionfor repeated tries. A continuous normal distribution isapproximated in =SuperStar= as the sum of ten inde-pendent events, each with 65,536 equally probable out-comes.

The user specifies the one sigma deviation.Approximately68.3% of component values fall within the one sigma limit.Approximately 99.7% of component values fall withinthree sigma limits. A significant number of values exceedone sigma deviation. Components outside three sigmalimits are relatively rare.

# SAMPLES: This specifies the number of sample runs toinclude in each Monte Carlo analysis.


SEED: Random numbers used for component distributionare derived from the specified seed. Enter an integer seedbetween -32768 and +32767. Runs with the same seed,circuit file and sample size are identical. This provides theuser with both the ability to repeat a specific run or tocreate 65,536 different runs of a specified sample size.

GENERATE REPORT: Checking this box causes MonteCarlo to generate an ASCII text file containing a detaileddescription of the run. For each sample an entry is in-cluded with component values and the resulting error.This file can be lengthy but it identifies component valuesets which result in poor performance. The file is giventhe same name as the current CKT/SCH file with a .MCGextension. Excerpts from such a text file are given in Table9-2.

Monte Carlo Report for ss4t81.ckt, Fri Oct 02 09:46:23 1992

Number of Samples: 25 Seed: 0Nominal Values: L,L1: 50 C,C1: 89 C,C2: 31L,L2: 125 C,C3: 13 L,L3: 62 C,C4: 696C,C5: 111 L,L4: 163 C,C6: 38

Round 1 L,L1: 52.5 C,C1: 93.356 C,C2: 32.5377L,L2: 127.061 C,C3: 13.6068 L,L3: 62.8945 C,C4: 715.683C,C5: 110.59 L,L4: 167.959 C,C6: 37.2387Yield Error: 0 PASSED....(rounds 2 to 12 appear here).....Round 13 L,L1: 49.6419 C,C1: 91.955 C,C2: 31.5196L,L2: 120.381 C,C3: 12.5782 L,L3: 61.2886 C,C4: 664.431C,C5: 105.546 L,L4: 155.142 C,C6: 37.0972Yield Error: 3.26268e-05 FAILED.....(rounds 14 to 24 appear here)....Round 25 L,L1: 49.9757 C,C1: 93.2691 C,C2: 29.4618L,L2: 131.235 C,C3: 13.5431 L,L3: 63.5674 C,C4: 693.017C,C5: 111.857 L,L4: 167.562 C,C6: 38.1538Yield Error: 0 PASSED

Final Yield: 21 of 25

Table 9-5 Sample *.MCG Monte Carlo generated report.


.MC FILE

Activating Monte Carlo automatically creates a file withthe circuit filename and the extension .MC if such a filedoes not already exist. This .MC file specifies a ±5%uniform distribution for all variables, a seed of 0, a samplesize of 25, and “no report.” User inputs in Monte CarloSetup overwrite these default specifications. This usercreated “.MC” file remains in effect for that circuit fileunless the “.MC” file is erased.

WORST CASE VS. MONTE CARLO

Shown on the left in Figure 9-5 is the response of thelowpass filter with all seven components stepped 5% in thedirection resulting in the poorest return loss near thecutoff frequency. Given on the right is the response withthe worse set of 5% stepped values resulting in the great-est shift in the cutoff frequency.

Table 9-6 Tolerance analysis for worse case return loss at bandedge (left) and worse case frequency shift up (right).


These conditions were found by manually tuning elementvalues while observing the responses. Different worsecase scenarios, such as return loss at low frequencies,require a different set of component values. Results arepoorer than the worst response encountered during theMonte Carlo run shown This is typical of the differencesbetween worse case and Monte Carlo analysis. As thenumber of components affecting the response increases, itbecomes unlikely that a run will exist where all values fallat extreme values in the direction causing the worst re-sponse. However, when only a few components affect theresponse, Monte Carlo is more likely to produce a nearworse case run. Also, if one component exhibits the great-est sensitivity, a near worse case run is more probable.

When a number of response specifications exist,more thanone set of worse case component values may exist. The setof component directions are typically different for differ-ent response specifications. Although Monte Carlo maynot find worst case responses, the user is relieved of thetedium of manually tuning several sets of worst casecomponent values.

YIELD BLOCK

The schematic file for a Monte Carlo run is identical to aschematic file for analysis, tuning or optimization, excepta YIELD block can be added which specifies responselimits for a successful unit.

The Yield block is identical to an OPT (optimization) blockexcept the “=” and “%” operators are not used because theyield would be zero. The “>” and “<” operators are used tospecify the range of output parameters which constitute asuccessful unit. The OPT block is used to find componentvalues which result in the desired nominal responses. TheYIELD block is used to set acceptable limits for definition


of what is a successful unit during Monte Carlo analysis.An example amplifier YIELD block might be:

YIELD50 950 S21>11.5 S11<-10 S22<-1050 950 S21<12.5

specifies that all passes with a gain between 11.5 and 12.5dB, and with better than 10 dB return losses, are success-ful passes.

When the circuit file includes the YIELD block, thenumber and percentage of passes which meet the targetsare displayed during a Monte Carlo run. A sample YIELDblock is given for the lowpass in Table 9-1. For thisexample, the yield was 26 out of 50 samples for a yield of52%.

If a YIELD block does not exist in the circuit file, the MonteCarlo paint occurs, but the error is computed as zero andthe yield is 100%.

The rules and options for use in the YIELD block arenearly identical to the OPT block and are defined inChapter 5. Although the rules and options are identical,the philosophy for using the optimization block are differ-ent for Monte Carlo analysis and circuit optimization. Ifthe above goals were used to optimize the amplifier, theresponse would likely be close to either 11.5 or 12.5 dB, atleast at some frequencies. Using this same block in MonteCarlo would then result in a poor yield. Instead, using anOPT block for circuit optimization

OPT50 950 S21=12 S11<-10 S22>-10

would tend to center the gain response at 12 dB. Then,using a YIELD Block for Monte Carlo limits of 11.5 to 12.5dB would produce a better yield.


The error value reported during optimization, tuning andMonte Carlo are all computed by the same algorithm, andtherefore relate directly to each other.

The OPT block is not used by Monte Carlo.

SENSITIVITY ANALYSIS

Selecting “Sensitivity” from the Statistics menu displayssensitivity plots in sequence for each component valuemarked with a “?” in the circuit file. Display pauses forviewing for each variable until the user strikes the Enterkey. In each sensitivity plot, the responses are displayedwith components at the nominal and specified deviationup and down values. The deviation values are the limitsfor uniform distribution, and the one-sigma values fornormal distribution.

Sensitivity analysis is useful for characterizing and iden-tifying individual relationships between components andthe circuit responses. It is yet another tool to assist thedesigner with understanding circuit behavior and manag-ing production yield.

DESIGN CENTERING

Optimization finds specific component values which pro-vide the best flatness, return loss, etc. However, whencomponents assume a range of values due to tolerances,the optimized nominal values may not be the best valuesfrom a yield perspective, particularly if the objective func-tion errors are different for equal component steps up anddown in value.

Design centering is a process which attempts to maximizeyield by adjusting the nominal component values so theobjective function errors are equalized. Design centeringis more likely to increase yield if component tolerances areloose.


Consider the example Chebyshev lowpass filter in Figure9-1. The Monte Carlo run shown in Figure 9-4 resulted ina yield of 52%. (There was no yield block for the bandpassso it was not included in yield calculations.) From theStatistics menu, “Design Centering” was selected. After10 runs of design centering, the yield was improved to 72%.

You may find the following remarks helpful for DesignCentering:

• Optimize completely before Design Centering.

• When testing a centered design, use Monte Carlo samplesizes > 200.

• Monte Carlo and Design Centering are statistical. Runswith different seeds vary significantly. Don’t expect exactyield prediction.

• Design Centering is a fine adjustment. Precise circuitmodeling is required. Include all possible componentparasitics before proceeding.

YIELD OPTIMIZATION

Yield Optimization is a new feature in Version 6 of =Su-perStar=. Yield Optimization is typically far more effec-tive and its use is now recommended over DesignCentering.

Yield Optimization finds element values based on thefollowing equality:

where

∀ ==

∑j

j j mm

n

Vn

V, ,

1

1

V the jthof k values with sj = ?

V V for the mth sample if yield is goodj m j, =

n number of samples where yield is good=


The principle of Yield Optimization is simple. It simplyaverages the element values for all the samples whichsatisfy the yield conditions. This simple principle is themost effective technique we have found for improvingyield.

To lauch Yield Optimization from the Statistics menuselect Yield Optimization. The window shown in Figure9-6 appears. The Fastest option confines the search to anarrow spread of element values around the nominalvalues. It results in a fast solution, but the best yield maynot be found. The Slowest option searches over a widerspread of element values. Fewer samples result in asuccesful yield and progress is slowed. However, improvedyield is likely because element values are averaged overthe widest possible range of values which result in success.During a Yield Optimization, if the output display “samplehits” is usually zero, select a faster search option.

You may recall that the original yield of the lowpass filterexample was 52%. Design Centering improved the yieldto 72%. On a 75 MHz Pentium machine, Yield Optimiza-tion with the Fastest option resulted in a 80% yield within8 seconds, the Medium option achieved a 96% yield in 17seconds and the Slowest option achieved a 100% yield in50 seconds.MONTECARLOSCREENDUMPS

Pressing Alt+F7dumps the entirescreen to the in-stalled printerand Alt+F8dumps the activewindow.

Table 9-7 Openning window for YieldOptimization


Monte Carlo screen dumps must be initiated with func-tion keys! Menu initiated dumps and plots will outputnominal-value single sweeps only.

Monte Carlo paints “exist” on the screen only. Data for themultiple sweeps are not stored in memory. Once the menupops down over the screen, the image is corrupted, sonormal single-sweep update is performed.


Chapter 10

EXPORT

Note:You must purchase =SCHEMAX= to use the Exportmenu.

EXPORTING CIRCUIT FILES

The Export menu allows Eagleware programs to writenon-native circuit file formats. This allows users to runSPICE and/or Touchstone circuit simulators with theirEagleware files. Touchstone circuit files are similar to=SuperStar= circuit files and are generally a one-to-onetranslation. A Touchstone file can also be exported froman Eagleware synthesis program via its Export menu.Exporting a SPICE circuit file requires some setup and isinitiated from =SCHEMAX=. A limited equation transla-tion capability has been incorporated.

EXPORT MENU OVERVIEW

The first menu item, Export Touchstone File, is availablein the synthesis and =SuperStar= programs. The remain-ing menu items are related to exporting a SPICE file andare available only through =SuperStar=.

Export Touchstone File takes the current schematic orsynthesized circuit and writes a netlist file for the Touch-stone linear circuit simulator from HP/EEsof . We recom-mend using the default extension .TCH to avoid confusionwith .CKT files for =SuperStar=. Export Touchstone File

is available in =SuperStar= and all synthesis programsthat write =SuperStar= circuit files.

Export SPICE File takes the current schematic file andwrites a SPICE file. SPICE Preferences and User SPICEText are also used in creating the SPICE file and theyshould be inspected and completed before writing theSPICE file.

Edit SPICE Command Text edits the user defined SPICEtext that is placed in the SPICE file created by WriteSPICE File. This text may contain anything you choose toenter, including comments. It is intended for SPICE DotCommands and library references (e.g., the print com-mand .PRINT).

SPICE Preferences presents a dialog box of settings re-lated to SPICE file exporting. For example, certain oscil-lators are analyzed in =SuperStar= as open loop. The loopis closed for a SPICE analysis. Also terminations are oftenhandled differently in =SuperStar= and SPICE analysis.These settings are local to the current .SCH file and shouldbe checked before exporting a file to SPICE.

Show SPICE Details is a toggle that adds SPICE specificinformation to the normal =SCHEMAX= part details dia-log boxes. The information displayed consists of theSPICE device used for translation, a parameter field foradding data on SPICE device line, and a sample outputline displaying the final translated SPICE line. To open aPart Detail dialog box, simply double click on any part,and=SCHEMAX= will display that part’s detail box.

TOUCHSTONE EXPORT EXAMPLE

In this example,=M/FILTER= is used to design a 5th-orderstepped-impedance lowpass microstrip filter on a 32 milteflon substrate with ½ ounce copper metallization. Thephysical line dimensions are optimized in =SuperStar= for

100 EXPORT

nstewart

Text Box

PTFE

discontinuity and rolloff compensation, and the resultingcircuit is then exported for use in Touchstone.

Start =M/FILTER=. Load the pre-saved =M/FILTER=configuration file by selecting “Open” from the File menuand selecting LP_STEPZ.MF$ from the EAGLE\EXAM-PLES directory. The screen should look like Figure 10-1.

Select “Write CKT” from the button flow chart, and writea physical circuit file. Name the file TEST, and select OK.Next, select “Run SS” to launch =SuperStar= for line-length and width optimization. Select “Automatic” fromthe Optimize menu in =SuperStar= to begin optimization,and press Esc when the screen resembles Figure 10-2.The example circuit was optimized for about 50 rounds.Press F2 to save the new circuit (replacing values).

Return to =M/FILTER= by selecting “Run =M/FILTER=”from the Shell menu. Now, press Load Values to load theoptimized values from the circuit file. Press the WriteCKT button, and select Write Touchstone Physical. Name

Figure 10-1 =M/FILTER= Screen For Touchstone Example

EXPORT 101

the file TEST, and select OK. Now the file TEST.TCHready to be simulated in Touchstone. You can start Touch-stone and load TEST.TCH from the EXAMPLES directory.

EXPORTING TO SPICE

Exporting SPICE files is performed from =SCHEMAX=.This is because many SPICE device models are signifi-cantly different than linear simulator models. Termina-tions are often handled differently in SPICE and linearsimulators. In =SuperStar=, oscillators are analyzed openloop while the loop is closed for SPICE analysis. Thesedifferences are resolved in =SCHEMAX=.

Because of variations in SPICE formats, many of theseresolutions are handled manually. Back loading (annota-tion) is not supported; any changes made to an exportedSPICE file cannot be loaded back into =SCHEMAX=.

Examine the SPICE Preferences item in the Export sub-menu. This menu item presents a dialog box containing

Figure 10-2 =SuperStar= Screen For Touchstone Example

102 EXPORT

SPICE related export options. The dialog box is preloadedwith default values which may be changed if required.Here is a quick look at the dialog fields and their usesfollowed by a more detailed discussion of each field.

Primary Circuit: =SuperStar= supports up to 10 simul-taneous output windows. Multiple output windows maybe used to display different networks. SPICE files can onlycontain one network. This dialog field selects which net-work to use for SPICE translation if more than one net-work is defined in =SCHEMAX=.

Some circuit networks are listed twice in the formNAME(Zo) and NAME. The first form comes from aWINDOW block defined in the text portion of the circuitschematic. The second form comes from the circuit net-works defined in the schematic. If you choose the firstform for your Primary Circuit, the Input and OutputImpedances are set to the values specified in the WIN-DOW block line. For example, a WINDOW block usingnetwork FILTER(50,150) will place FILTER(50,150) inthe Primary Circuit selection list. Choosing this PrimaryCircuit presets the Input/Output Impedances to 50 and150, respectfully.

Target Version: This field specifies the SPICE simulatorformat to use. Options are generic SPICE2 and SPICE3(developed at University of California, Berkeley), PSPICE(a SPICE2 derivative from Microsim), and IsSPICE (aSPICE3 derivative from Intusoft).

Input/Output Impedances: These values can be editedif standard terminations is selected and the Primary Cir-cuit does not have specified impedance terminations. Forexample, if you have chosen LowPass(300) as your Pri-mary Circuit, then the input/output impedances are fixedat 300 Ohms. If you had chosen LowPass instead ofLowPass(300), then the impedances may be edited.

EXPORT 103

Terminations:

• Standard : The terminators specified in the text portion ofthe schematic are included in the SPICE file. Theseterminations are shown in the Impedance In/Out fields.This is the default selection.

• Exclude : The Impedance terminators are excluded fromyour SPICE file. You should use this option instead ofsetting the terminator values to zero which may causeerrors in SPICE simulators.

• Closed Loop : This connects the circuit output to its input.A use for this option is oscillator analysis. One method ofoscillator analysis in =SuperStar= is examination of theopen loop cascade gain and phase. For SPICE analysisthe loop is closed.

• Grounded Input : The Terminators are excluded and thecircuit input is grounded. A second method of =SuperStar=oscillator analysis is to examine the reflection coefficient ata port of a negative resistance oscillator. With SPICEanalysis this port is grounded.

When standard terminations are selected, a 2 Volt Inde-pendent Voltage Source and terminating resistors areincluded. When other termination options are selected, itmay be necessary to add a signal source to the SPICE file.

Ignore Warning Messages: warning messages may oc-cur during translation for various parts. These messagesappear on screen and are included in the translatedSPICE file. This option prevents the display and export ofWarning Messages. (Error Messages are still shown.)

HOW PARTS TRANSLATE TO SPICE

There are three categories of part translation to SPICE:Direct, Incompatible, and Compound. For translations forspecific parts, see Chapter 12, Element Reference.

Direct parts are translated on a one-to-one basis. Exam-ples include CAP, IND, RES, Signal Ground (Voltage

104 EXPORT

Source), TLE, TLE4, TLP, and TLP4. Incompatible partsare those that have no simple SPICE equivalent, includingphysical models, S- or Y-parameter devices, and internaltransistor models (FET and BIP).

Compound parts are parts that are translated as SPICEsubcircuits. They include MUI, OPA, VCC, and XTL. Thisprovides comparable simulations in =SuperStar= andSPICE. For example, an Eagleware VCC is modeled bytwo resistors and a voltage controlled current source. Touse just the SPICE VCC device without the resistors, youmay override the default translation by double-clicking onthe VCC device. This presents the Part Details dialog box.Select ‘G’ from the SPICE Device list and click the OKbutton to save the changes.

Some special notes on Compound parts are:

• The SPICE opamp E model (=SuperStar= translates OPAas an ‘E’ model) is ideal in that the unity crossoverfrequency is infinite. You may substitute a SPICE librarymodel or subcircuit for the opamp. Most opampmanufacturers have SPICE Models for their products.

• The =SuperStar= TRF device (Ideal Transformer) is notsupported in SPICE. You should specify an MUI (Mutuallycoupled inductors). You will need to specify appropriatewinding inductance and coupling.

• The =SuperStar= FET and BIP devices do not include anybiasing information and so are not translated. You mayindividually specify how to translate these parts by definingthe translation device in the Part Details dialog box.

Incompatible Parts are identified in the translated SPICEfile with exclamation point (!) at the front of the part line.A SPICE model (.MODEL) or subcircuit may be assignedto that part in the Part Details dialog box. You must alsoplace a SPICE Model definition (.MODEL block) in theexported SPICE file. This is done either through SPICECommand Text or manually after exporting. If the SPICE

EXPORT 105

simulator supports libraries (both PSPICE and IsSPICEsupport libraries), the library reference is included inSPICE Command Text entries.

SPICE COMMAND TEXT

The SPICE Command Text editor is accessed by selectingEdit SPICE Command Text from the Export menu. Youmay enter SPICE Control Line commands, library includecommands and remarks for inclusion in the exportedSPICE file. An Example SPICE Command Text list is:

.INCLUDE RF.LIB

.TRAN 20N 25000N UIC

.PRINT TRAN V(5)

This example is for IsSPICE4 from Intusoft. The first linespecifies the library location for a transistor model usedin the SPICE file. The second line requests a transientanalysis from t=0 to 25,000 nS in 20 nS increments. Thelast line is a request to list the transient voltage at node 5in the output print file.

For a detailed explanation of SPICE Control Line com-mands, please refer to your specific SPICE manual.

EQUATION SUPPORT

=SuperStar= and =SCHEMAX= support the definition ofpart values via mathematical expressions. Equation sup-port in Touchstone and many SPICE simulators is morelimited. Therefore, simple variable assignments aretranslated, but models, equations with arithmetic opera-tors,and functions are not supported. For example: in yourEQUATE block, you may set variable C1=50 or C1=?50and use it as a value for a Capacitor, and you may even useC2=C1. You may not use C2=C1+50, since it uses anoperator (+).

106 EXPORT

SPICE DEVICE NAMING CONVENTIONS

In =SCHEMAX=,part names are optional. This is not truein SPICE,since each part name represents the type of partas well as the part’s unique identity. A standard namingconvention was adopted for translating =SCHEMAX=part names into SPICE part names:

• The first character is the part type, as required by SPICE.

• The first character is followed by a unique number for thegiven part type.

• If a name was assigned to the part in =SCHEMAX=, thenthe next character is an underscore followed by theassigned part name.

• The names of compound parts follow the same convention,however, the compound subcircuit implementation nameadds an X$ to the beginning of the name.

• User defined subcircuits use the user specified namewithout modification (it is up to the user to keep thesenames unique).

Here are some examples of this naming convention:

=SCHEMAX= Part Resulting SPICE PartCAP 1 2 C=25 C1 1 2 25pFCAP 3 4 C=50 Name=Joe C2_Joe 3 4 50pFIND 2 3 L=150 Name=Joe L1_Joe 2 3 150nHMUI 5 6 0 0 . . . Name=MUI X1_MUI 5 6 0 0 X$X1_MUINETWORK 7 8 0 X2_NET1 7 8 NETWORK

SPICE EXPORT AND ANALYSIS EXAMPLES

The following examples illustrate the integration ofSPICE simulation in the GENESYS environment. For amore complete understanding of SPICE methods and ca-pabilities please refer to the documentation provided withyour SPICE product.

The SPICE examples were run using IsSPICE4 from In-

EXPORT 107

tusoft. These SPICE example files are found in yourEAGLE\EXAMPLES directory.

EXAMPLE 1 - SPICE1.SCH

This example contains an MUI device (a compound part)that will be translated into a SPICE subcircuit and theSPICE Control Lines to generate SPICE’s AC Small SignalAnalysis. Capacitor C is changed to 21.11pF causing thetransmission notch to be centered at approximately 100MHz. In this example, you will:

• View and modify the SPICE Preferences dialog.

• Use SPICE Commands to generate an AC Small SignalAnalysis.

• Examine how Export handles Compound Parts intranslation to SPICE format.

Load SPICE1.SCH from the EXAMPLES directory.Choose SPICE Preferences from the export menu. Checkthe Primary Circuit selection, it should be BRIDGE(75).Choose your Target Version; this example uses IsSPICE.Since the impedance is specified in the Primary CircuitListbox, they are fixed at 75 Ohms and are gray (i.e., theymay not be edited). Finally, notice the Standard Termina-tion radio button has been selected for this file; this pro-vides the circuit with a 2 Volt source and 75 ohmterminating resistors. Once you are satisfied with thesettings, choose OK to exit.

Next,you will add text SPICE commands to the export file.To complete this task you must be familiar with SPICEcommands. In this case, the only analysis of interest is theAC Small Signal Analysis. To view/edit the SPICE Com-mand Text, select Edit SPICE Command Text from theExport menu. The following should be displayed:

* This example was tested in IsSPICE v4.0 and PSPICE v6.* .AC performs an AC analysis from 90 to 110 MHz.* .PRINT outputs the voltage at node 6 in tabular form.

108 EXPORT

* .PLOT outputs the voltage at node 6 in text graphical form.

.AC LIN 101 90MEG 110MEG

.PRINT AC V(6)

.PLOT AC V(6)

The MEG after the frequency numbers is a Scaling Factor(a list of these appears at the end of this chapter). Theyspecify the scale (units multiplier) for a part value. The.PRINT command generates a response similar to the=SuperStar= command GPH S21 -30 0. The .PLOT com-mand creates a text based graph designed for output to aline printer.

Select Export SPICE File from the Export menu. Thedefault filename for the SPICE file will be SPICE1.CIR.Press the OK button to accept the name and write the file.If the file exists, you will be asked if you wish to overwritethe file; answer Yes. After the SPICE file is written atranslation successful message is displayed. To test thisSPICE file, load it into your SPICE simulator.

1 2

1 3

0

43 05

2

3

0

1 1

66

R1

75 ohm

R2

75 ohm

R3

75 ohm

R4

?75 ohm

C

?21.11

BRIDGE

L

120 nH

MUI

50000 nH 50000 nH

K=.999

Figure 10-3 Schematic of SPICE Example 1 (SPICE1.SCH)

EXPORT 109

When the MUI in =SCHEMAX= was translated to SPICE,Export created three parts to represent the original MUI.TRF and MUI are similar in =SCHEMAX=, however, TRFdoes not translate to SPICE because it is incompatiblewith SPICE algorithms. TRF must be replaced with MUIbefore SPICE simulation.

Compound part subcircuit names are Xn_name and theassociated subcircuit is called X$Xn_name. This “X$” con-vention allows you to immediately identify a subcircuit asa compound part from =SCHEMAX=. All user subcircuits,called networks in =SCHEMAX=, are simply called bytheir given names.

EXAMPLE 2 - File: SPICE2.SCH

This is a modified version of the AUDIODPX.SCH file.This audio frequency diplexer contains several opampsand provides about 18dB of gain in both the lower andupper passbands. The cut-off frequencies are 1KHz. =Su-

Figure 10-4 =SuperStar= Simulation For Example 1

110 EXPORT

perStar= provides the amplitude and group delay re-sponses. Generic SPICE provides only the amplitude re-sponses. PSPICE or IsSPICE is required for group delay.

Tasks:

• Multiple circuit simulations with SPICE.

• The use of some common PSPICE analysis commands.

• Examine the OPA (opamp) compound part.

Once the file is loaded, choose SPICE Preferences from theExport menu. The Primary Circuit selection should beLOWRESPONSE(8). Select a Target Version; this exam-ple uses IsSPICE commands. Since the impedance isspecified in the Primary Circuit listbox, they are fixed at8 ohms. Notice the Ignore Warnings checkbox has beenselected. Each opamp generates a warning message indi-cating that the opamp is ideal and does not include thecross-over frequency specified in =SCHEMAX=. Once youare satisfied with the settings select OK to exit.

Figure 10-5 SPICE simulation for Example 1

EXPORT 111

To view and edit the SPICE Command Text, select EditSPICE Command Text from the Export menu. The follow-ing should be displayed:

*Target version for this example is IsSPICE

* This example was tested in IsSPICE v4.0 and PSPICE v6.* .AC performs an AC analysis from 1Hz to 2KHz.* .PRINT outputs the voltage at nodes 20 and 21.

.AC LIN 101 1Hz 2KHz

.PRINT AC V(20)

.PRINT AC V(21)

Since =SuperStar= works with two port circuits, this sche-matic contains two primary test circuits (LowResponseand HiResponse). The output nodes are swapped betweenthe two networks and the unused node is terminated with8 ohms. This is the test method using a network analyzer,which is how =SuperStar= is designed to operate. SPICEinherently provides multiple node “probing” so redefiningthe circuit is unnecessary. There are two .PRINT state-

1

1

0

2

3

0

2

4

4

0

5

6

0

2

7

7

0

8

8

0

9

9

0

10

10

0

8

11 8 12 10

13 14

15 16

16 2 17 5

6

5

14

3 17

1118 12

55

10

13

1211

16 17

8

2 5

10

0

19 20

0

19 21

0

19

19

19 19

022 23

0

22 24

0

22

22

22 22

R3

33000

R4

20000

C2

7500

R7

12000

R8

20000

C4

7500

R11

33000

R12

20000

R15

12000

R16

20000

R9

12000

R13

20000

R10

12000

R14

20000

R1

39000

R2

39000

C1

7500

C3

7500OPA2

OPA4

OPA1 R5

22000

R6

22000

C5

7500

C6

7500

C7

7500

C8

7500

OPA3

LOW_NETWORK

HI_NETWORK

LOW_NETWORK

HI_NETWORKLOWRESPONSE

Rterm

8 ohm

LOW_NETWORK

HI_NETWORK

Rterm

8 ohm

HIRESPONSE

Figure 10-6 Schematic of SPICE Example 2 (SPICE2.SCH)

112 EXPORT

ments in the command text. Node 20 is the output for theLowPass subcircuit and node 21 is the HighPass subcir-cuit. The “HIRESPONSE” circuit required for =Super-Star= is simply redundant for SPICE and is not needed.

OPA is a compound part. The SPICE opamp model doesnot include gain roll-off with frequency. If the operatingfrequency of the circuit is not significantly lower than thebandwidth of the actual opamps being used, simulationinaccuracies are introduced. To model opamps in SPICEmore accurately a library subcircuit model should be used.Opamp libraries are available with many SPICE simula-tors and others are available from opamp manufacturers.In this example, the frequencies are low (below 2000 Hz)and should not present a significant problem.

Select “Export SPICE File” from the Export menu. Thefile exported from this example is SPICE2.CIR. To viewthe frequency response, add trace “20*log10(V(20)/V(19))”or “VDB(20)-VDB(19)”. This gives E21 as the ratio of theoutput voltage over the input voltage.

Figure 10-7 SPICE Simulation For Example 2

EXPORT 113

EXAMPLE 3 - File: SPICE3.SCH

This example uses a file (Q2N6618) from the Intusoft RFLibrary (RF.LIB, © 1995, Intusoft). The library is a highquality collection of RF devices and is available for usewith their IsSPICE simulator. This library makes Is-SPICE an ideal choice for RF SPICE simulations.

This is a 125 MHz bipolar oscillator created in =OSCIL-LATOR= using a 2N6618 bipolar NPN transistor(10V/3mA). This transistor is modeled in =SuperStar= bya TWO device (S-parameter data file 2N6618A.S2P). ASPICE model for the transistor has been included in theexample directory as Q2N6618.TXT. (See the note above.)

The =SuperStar= open-loop analysis in Figure 10-11 indi-cates sufficient loop gain for oscillation and the phase zerocrossing (oscillation frequency) occurs at approximately128 MHz. The book Oscillator Design and ComputerSimulation discusses oscillator design in detail, including

Figure 10-8

114 EXPORT

additional oscillator simulations using SPICE.

In this SPICE example we will:

• Model a TWO device with a SPICE transistor library model.

• Setup a transient analysis of the oscillator circuit.

• Add a model reference in SPICE Command Text.

Once the file is loaded, select SPICE Preferences from theExport menu. The Primary Circuit selection should beLOOP. Choose the Target Version; this example is tar-geted for IsSPICE. Terminations is set to Closed Loop.The Closed Loop setting causes Export to connect theinput node directly to the output node via a 0 Volt powersource in the resulting SPICE file. This simply serves asa zero ohm connecting element. Select OK to continue.

In =OSCILLATOR=, a TWO device was used to inputS-parameter data to model the transistor. In SPICE amodel or subcircuit must be used for this part. Transistormodels and libraries are available from part manufactur-

Figure 10-9 EXAMPLE3.OS$

EXPORT 115

ers and SPICE software developers.

To specify a library model, the Part Details dialog box forthe transistor is opened from the schematic by selectingthe part and pressing F4 or by double clicking the part.Select “X Subcircuit” as the device type in the Device listbox under SPICE Information. Next, specify the subcir-cuit name (Q2N6618) in the Parameters field. The Outputfield then displays the SPICE text line that is generatedwhen the file is Exported.

The subcircuit must use the same number of nodes asyour part. In this case, the TWO part has three nodesand the subcircuit (Q2N6618.TXT) has three nodes.

Next we proceed to the SPICE Command Text to setup thetransient analysis and add the transistor subcircuit defi-nition. The SPICE Command Text edit window should be:

* Target Version for this Example is IsSPICE v4.0* This example was tested in IsSPICE v4.0 and PSPICE v6.

Figure 10-10 =SuperStar= Simulation For Example 3

116 EXPORT

* .TRAN performs a Transient Analysis to 2000 nS.* .PRINT outputs the Transient Voltage at the output node.

.TRAN 2N 2000N UIC

.PRINT TRAN V(6)

* To use the 2N6618 Transistor .SUB file:* For SPICE2 and SPICE 3, Copy text from* file Q2N6618.TXT to here

* The next line includes the file for IsSPICE*Include Q2N6618.TXT ;Change the * to a . for PSPICE

The transient line (.TRAN) requests a circuit transientanalysis (oscillator starting waveform). This is resourceintensive and requires significant processor power andsystem memory. SPICE simulator requirements vary.Please check your SPICE documentation for running re-quirements. For example, this simulation in PSPICE withthe .PROBE command requires about 14MB of hard diskspace and 20 minutes on a 486/DX-33.

Figure 10-11 SPICE Simulation For Example 3

EXPORT 117

The UIC parameter tells SPICE to Use Initial Conditions.This facilitates starting. Alternatively, UIC may be omit-ted and the supply specified as pulsing on at t=0. The.PRINT command causes SPICE to print the transientvoltage at the output node (node 6).

The next section of the text involves the subcircuit line“X1_2N6618 6 3 0 Q2N6618". The specific format for in-cluding the subcircuit data for the 2N6618 transistor isSPICE version dependent. PSPICE uses a SPICE DotCommand (.INCLUDE) and IsSPICE uses either a SPICEDot Command (.INCLUDE) or a special comment format(*INCLUDE). The file Q2N6618.TXT contains the subcir-cuit definition for the 2N6618 NPN transistor. If yourSPICE simulator does not support file inclusions, then youcan simply cut and paste the text from the data file intothe SPICE Command Text window. In this example, theIsSPICE *INCLUDE was used.

Select Export SPICE File from the Export menu. The fileexported from this example is SPICE3.CIR. An IsSPICEtransient analysis graphical output screen is given inFigure 10-12. Oscillation starts in approximately 30 nSand builds to 4 volts peak-to-peak. The oscillation fre-quency determined from the time period agrees with the=SuperStar= analysis.

SPICE SCALING FACTORS AND GENERAL RULES

SPICE values are given in base units, such as Ohms,Farads, Henries, Hertz, Volts, Amps, etc. Because =Super-Star= uses modified base units by default (i.e., picofarads,nanohenries, megahertz, etc.), EXPORT automaticallyuses the appropriate scaling factors. If you use transla-tions for parts other than the default translations, youmust be careful to use the correct units.

General SPICE Syntax Rules:

118 EXPORT

• All characters must be in CAPS.

• Node 0 (zero) is always Ground (GND).

• Each field must be separated by a delimiter.

• Delimiters are: one or more spaces, a comma, anequal-sign, or a left\right parenthesis.

• Name fields must begin with the letter (A-Z) which denotesthe component device type.

• Name fields may contain additional alphanumericcharacters (A-Z, 0-9).

• Numeric fields may be either an integer (INT) or a floatingpoint (FP) value;

• An * denotes a comment line; the asterisk must be the firstcharacter on a line (column 1; no spaces or tabs).

• An INT or FP value may be followed by an integerexponent (12.44e6) or by a scaling factor (12.44MEG).

• Any alphanumerics immediately following a scaling factorare ignored (12.44Megavolts = 12.44e6 = 12440000).

• Please note the use of M, MEG, and MIL (22MILlivolts =22x.0254 volts = 0.558 volts, NOT 0.022 volts)

SPICE2 Specific:

• Node fields are treated as integers (i.e., 0 and 00 are thesame node).

SPICE3 Specific:

• Node fields are treated as arbitrary strings (i.e., 0 and 00are NOT the same node; node AAA is a legal node name).

PSPICE Specific:

• Node fields are treated as Character strings (i.e., 0 and 00are NOT the same node).

• A semicolon (;) denotes an inline comment.

• Lowercase characters are allowed.

IsSPICE Specific:

EXPORT 119

• Node fields are treated as character strings (i.e., 0 and 00are NOT the same node).

• A semicolon (;) denotes an inline comment.

• All lines must start in column one, no spaces or tabs.

• Lowercase characters are allowed.

Scale Factors Value Nomenclature

T 1E12 Tera

G 1E9 Giga

MEG 1E6 Mega

K 1E3 Kilo

M 1E-3 Milli

U 1E-6 Micro

N 1E-9 Nano

P 1E-12 Pico

F 1E-15 Femto

MIL 2.54E-5 Mil

Table 10-8 SPICE Scaling Factors

120 EXPORT

Chapter 11

Examples

T his chapter contains many application examples.Not only do they help you learn how to use =Super-Star=, but many of these examples are interesting

solutions to classic RF and microwave design problems.They can be the beginning of your own library of solutionsto problems you face every day.

The example files are located in the EAGLE\EXAMPLESdirectory.

=SCHEMAX= vs TEXT CIRCUIT DESCRIPTIONS

A circuit may be described to =SuperStar= by drawing aschematic in =SCHEMAX= or by entering a text net listin a text editor built into =SuperStar=. The default exten-sion for schematic description files in =SCHEMAX= is*.SCH. The default extension for text net lists is *.CKT.

When using =SCHEMAX=, after drawing a schematic, thedesired output formats, the sweep description, any optimi-zation goals, and any equations are entered into the textportion of the SCH file. The text portion of the SCH file isidentical to the same section of a text net list file. Thesetext portions of the SCH file are included in the followingexamples. The text net lists are not listed here but theyare distributed with the software with the extension CKT.

EXAMPLE 1 - BRIDGE_T.SCH

This is a bridge-T highpass filter. Notice that the inputremains matched, even in the stopband of the filter. Thisis achieved when Zo = R = SQR(Xc * Xl).

This simple example illustrates display of the results inboth graphic and tabular format. The tabular windowunder the graphic display window uses the SD optionwhich displays all S-parameters in decibel magnitude andthe group delay. The tabular window on the right is usedto display only S21. Chapter 4, Window Blocks, is devotedto describing output display formats.

1 2 3

0

1 31 3

R1

50 ohm

R2

50 ohm

L1

?120 nH

C1

?47 pF

BRIDGE-T

122 Examples

WINDOWBRIDGE_T(50)GPH S21 -30 0GPH DLY 0 5POL S11 -36POL S22 -36FREQSWP 0 200 41

WINDOWBRIDGE_T(50)DSP SDFREQSWD 0 200 20

WINDOWBRIDGE_T(50)DSP S21FREQSWD 0 200 20

Examples 123

EXAMPLE 2 - WILKSON.SCH

This is a simple Wilkinson equal power splitter/combiner.It includes an optimization block which was used to findthe listed values by optimizing the original ideal electricaldesign to compensate for the physical discontinuities suchas the tees and corners.

This example also illustrates how to handle multiportnetworks. New in Version 6 of =SuperStar= is the abilityto directly specify parameters such as S31 and S33.Please refer to the WINDOW specification in the textportion of this example.

When the schematic is drawn, the user enters a portnumber in the Dialog box for the output symbol. =SCHE-MAX= assigns a default port number of 1 to the input port.

R1

?82 ohmWILK(1)

(2)

(3)

TL1

W=W1

L=L1

TL3

W=W3

L=L3

TL2

W=W2

L=L2

TL4

W=W2

L=150

TL5

W=W3

L=150

TL6

W=W2

L=200

TL7

W=W2

L=200

124 Examples

Examples 125

EXAMPLE 3 -BALANAMP.SCH

This is 2100-2900 MHz balanced amplier. This exampleillustrates microstrip design, the branch line coupler, theNET component, displaying two different networks on onescreen, and the =LAYOUT= module.

The single-ended amplifier used in this balanced circuit isshown at the top. It is given the name AMP at its input.The return loss of the SE amp is shown on a Smith charton the left on the next page. Notice the poor return loss.

The balanced amplifier is built using branch line couplersto split the input signal and later to combine the signals.The SE amp is duplicated in the balanced amplifier usingthe NET component. NET is given the designator AMP.As components in the SE amp are optimized they effectboth amps in the balanced circuit. The branch line cou-plers deliver reflected signals to the terminating resistorsso the return loss of the balanced circuit is improved.

BRANCH(1)

W=W6

L=L6

W=W6

L=L6

W=W7

L=L7

W=W7

L=L7

W=W6

L=L6

W=W6

L=L6

W=W7

L=L7

W=W7

L=L7

Rt

50 ohm

Rt

50 ohm

(2)

Q1

R1

680 ohm

W=W2

L=L2

W=40

L=200

W=110

L=250

W=110

L=250

AMP(1)

(2)

AMP

AMP

C1

27 pF

W=W4

L=L4

W=W3

L=L3

27 pF

27 pF

126 Examples

Shown above is a finished layout of the balanced amplifier.This layout was created by selecting “Edit Layout” fromthe Layout menu in =SCHEMAX=. Footprints for thelumped elements and dimensioned metals are automat-ically placed on the layout page. You then select objectsand snap nodes together to resolve rubber band lines.

Examples 127

To duplicate the single ended amplifier in the layout, a fewextra steps are required:

1. Initially, the single-ended amplifier components and twoNET objects are placed in the layout. First, return to=SCHEMAX= and double-click on each NET object. In thedialog box, select the LAYOUT button and then chooseReplace with Open Circuit. This removes NET objectsfrom the layout.

2. Next, finish laying out the one SE amp. Draw a boxaround the SE amp portion of the layout and select Copyand Paste from the Edit menu in =LAYOUT=. Move theseduplicated components to the desired position.

128 Examples

EXAMPLE 4 - FILSOLEN.SCH

This example illustrates the synthesis of a lumped-ele-ment zig-zag elliptic bandpass filter and replacing electri-cal inductors with physical single-layer solenoid models.This example also displays a =SCHEMAX= window on thesame screen as a response window.

The zig-zag (minimum inductor) elliptic bandpass wassynthesized by =FILTER=. The zig-zag is available foreven order and it reduces the number of inductors re-quired by one for each transmission zero in the lowpassprototype. No other filter has better selectivity for anequal or fewer number of inductors.

After =FILTER= wrote the SCH file, the capacitors wereset to the nearest standard value and the inductors werereplaced with the AIRIND1 model. The form diameter is2.54mm, form length is 5.08mm, and the wire diameteris 0.5mm. Displayed in the schematic is the requirednumber of turns for each coil tuned for best response.

Examples 129

EXAMPLE 5 - COUP3SEC.SCH

Examples 2 and 3 illustrated Wilkinson and branch-linecouplers. Coupled-line couplers in microstrip do notacheive 3 dB coupling without exceptionally close lines.Therefore Wilkinson and branch-line networks are oftenused when equal splits are needed.

This example illustrates a 10dB microstrip coupler withthree sections for improved bandwidth.

MCP2COUPLER(1) (2)

(3)(4)

C2 pFC2 pF C1 pFC1 pF

MCP1 MCP1

EQUATEC1=?0.1C2=?0.3W1=?100S1=?136L1=?816W2=?56S2=?10L2=?860WINDOWCOUPLER(50)GPH S21 -3 0GPH S41 -20 0GPH S31 -40 0FREQSWP 500 2500 41OPT750 2250 S41=-10@10 S11=-20 S22=-20& S33=-20 S44=-20 S31=-30

MARKERS750 1200 1800 2250 750 1200 1800 2250WINDOWCOUPLER(50)SMH S11 -10FREQSWP 500 2500 41MARKERS750 1200 1800 2250 750 1200 1800 2250

130 Examples

In the above layout, the rubber band lines which connectthe three coupled microstrip sections were left unresolved.It is not absolutely neccesary to resolve rubber band linesif the metal is connected by a footprint or by a polygon ofmetal which you may add. In this case the lumped ele-ment capacitors, which improve the directivity, were usedto close the natural gap between line sections caused bydifferent line spacing.

Examples 131

EXAMPLE 6 - CONTIGUS.SCH

This example illustrates the design of a contiguous diplexfilter. It was designed by the following steps:

1. Design a 7th order singly-terminated Butterworth high-pass filter was in the =FILTER= synthesis program andwrite a file named CONTIGUS.SCH.

2. Return to =FILTER= without running =SuperStar=.Design a 7th order singly-terminated Butterworth low-pass and write a file named LP.SCH. Then run =Super-Star= and display the lowpass response.

3. Enter =SCHEMAX= and draw a box around the entirelowpass schematic. Selecting “Cut” and “Paste” from the

DIPLEXER(1)

C1

357.62 pF

L1

303.28 nH

C2

75.433 pF

L2

142.39 nH

C3

47.972 pF

L3

110.6 nH

C4

51.089 pF(3)

L1

44.269 nH

C1

52.2 pF

L2

209.88 nH

C2

111.18 pF

L3

330.01 nH

C3

143.14 pF

L4

309.88 nH(2)

WINDOWDIPLEXER(50)GPH S21 -60 0GPH S31 -60 0GPH S23 -60 0FREQSWP 0 80 81WINDOWDIPLEXER(50)GPH S11 -60 0

FREQSWP 0 80 81

132 Examples

Edit menu places the lowpass schematic in the buffer andback in the schematic.

4. Next, load CONTIGUS.SCH in =SCHEMAX= and selectPaste from the Edit menu which drops the lowpass overthe highpass. Drag the lowpass schematic off of the high-pass schematic using the mouse.

5. Connect together the two filters at the singly-termi-nated, zero-impedance ends and modify the text Windowblock to display the desired information.

The responses and isolation are shown on the left. Thereturn loss is shown on the right. Notice that the RL isexcellent through the entire crossover region. This is anatural and desirable consequence of designing diplexersby connecting together singly-terminated filters withidentical cutoff frequencies (contiguous). With lossless,ideal components, the RL is theoretically infinite at allfrequencies. Similar results are acheived using Cheby-shev filters with contiguous 3 dB corner frequencies.

Examples 133

EXAMPLE 7 - BIPMODEL.SCH

This is a model for a VHF bipolar transistor with packageparasitics. The parameters in the BIP model and thepackage parasitics are optimized to match the model tomeasured S-parameter data. This is often refered to as“parameter extraction”.

This example uses post processing. The last window sub-tracts the device measured data (defined in DATA) fromthe model (defined in BIPMODEL). The optimizationblock specifies that the difference of the magnitude andangle of the two networks should be zero.

This example also illustrates the ability to plot differentnetworks on one graph (note the line GPH DATA(50):S11).It is not necessary to have a window which displays thenetwork DATA.

BIP

Ls

?1 nH

Lo

?1 nH

Co

?1 pFCi

?1 pF

Li

?1 nHBIPMODEL(1)

(2)

2N5179

(2)DATA(1)

WINDOWBIPMODEL(50)SMH S11SMH DATA(50):S11SMH S22SMH DATA(50):S22FREQDIS 100 200 300 500 700 900

WINDOWBIPMODEL(50)POL S21POL DATA(50):S21POL S12

POL DATA(50):S12FREQDIS 100 200 300 500 700 900

WINDOWBIPMODEL(50)-DATA(50)DSP MAGANG[SPAR]FREQDIS 100 200 300 500 700 900OPT100 900 P11=0 P21=0 P12=0 P22=0100 900 S11=0@10 S22=0@10 S21=0@10 S12=0@10

134 Examples

Examples 135

EXAMPLE 8 - TUNEBP.SCH

This is a tunable filter using coupled transmission lines.This unique filter maintains relatively constant band-width over a 33% tuning range. The coupling of twoside-by-side transmission lines with the same endsgrounded approaches zero as the lines approach 90 de-grees electrical length. By properly choosing the electricallength, the coupling decreases with increasing frequencyat the correct rate.

This example illustrates the simultaneous optimization ofrelated networks, in this case to acheive constant band-width of 200 MHz. All three networks shown below sharethe same line length, width and spacing which are opti-mized parameters. They also share the same substrate,FR4 with a dielectric constant of 4.8. The varactors arenot shared. One network is optimized to a center fre-quency of 2000 MHz, another for 2400 MHz and the thirdfor 2800 MHz.

Optimization finds the common line dimensions and thecapacitor values needed to tune from 2000 to 2800 MHz.The display description, optimization blocks and resultsare shown on the next page.

(2)F2400(1)

C2400 pFC2400 pF

(2)F2800(1)(2)F2000(1)

C2000 pFC2000 pF C2800 pFC2800 pF

136 Examples

EQUATEW=?22S1=10S2=?70L=?341C2000=?1.18C2400=?0.765C2800=?0.503

WINDOWF2000(50)GPH S21 -30 0GPH S11 -30 0FREQSWP 1400 2600 51OPT1400 1600 S21<-151900 2100 S11<-152400 2600 S21<-25MARKERS1400 1900 2100 2600

WINDOWF2400(50)GPH S21 -30 0GPH S11 -30 0

FREQSWP 1800 3000 51OPT1800 2000 S21<-152300 2500 S11<-152800 3000 S21<-25MARKERS1800 2300 2500 3000

WINDOWF2800(50)GPH S21 -30 0GPH S11 -30 0FREQSWP 2200 3400 51OPT2200 2400 S21<-152700 2900 S11<-153200 3400 S21<-25MARKERS2200 2700 2900 3400

Examples 137

EXAMPLE 9 - AFILTER.SCH

This example illustrates how the complexity of activefilters can be traded against the sensitivity of the responseto op-amp performance parameters. The filters used forcomparison were synthesized using the =A/FILTER= pro-gram.

The top schematic is a single feedback, 5th order 0.1 dBChebyshev, lowpass filter. Only two op-amps are required.The bottom schematic is a lowpass synthesized to thesame specifications using the low-sensitivity topology. Itrequires five op-amps.

The solid traces give the responses with op-amp parame-ters as follows: Ri=1E6 ohms, Ro=75 ohms, Gdc=1E5 andFcrossover=10 MHz. The dashed traces show the re-sponses with the unity-gain crossover-frequency reducedto 1 MHz. Notice that the low-cost single feedback designhas greater peaking near the cutoff frequency and greatererror in the cutoff frequency.

The sensitivity of both designs to resistor and capacitortolerances is similar for this design. To view this circuit’sfrequency response, the parameter E21 must be usedinstead of S21. This signifies voltage gain instead of powergain.

SINGLEFB(1)

R1

1000 ohm

C1

14728.5 pF

R2

1000 ohm

R3

1000 ohm

C2

2223.4 pF

Q1C3

25986.8 pF

R4

342.29 ohm

C4

116337 pF

R5

342.29 ohm

C5

2700 pF Q2

(2)

LOWSENS(1)

R1

4557.6 ohm

Q1

R2

4557.6 ohm

C1

2700 pF

R3

2816.7 ohm

Q2

R4

3367.8 ohm

C2

2700 pF

Q3

C3

2700 pFR5

7374.3 ohm

Q4

R6

684.58 ohm

C4

2700 pF

Q5

C5

2700 pF

(2)

138 Examples

EQUATERi=?1E6Ro=?75Gdc=?100000Fc=?10

WINDOWSINGLEFB(1e-12,1e+12)GPH E21 -60 20GPH DLY 0 100000FREQSWP 0 0.048 101OPT0 0.024 E21=00.036 0.048 E21<-30

WINDOWLOWSENS(1e-12,1e+12)GPH E21 -60 20GPH DLY 0 100000FREQSWP 0 0.048 101OPT0 0.024 E21=00.036 0.048 E21<-30

Examples 139

EXAMPLE 10 - AMPSFB.SCH

This example illustrates four feedback amplifier topolo-gies. It is interesting to compare their gain, reverse isola-tion and match. Properly placed inductors and capacitorscan typically improve the responses. In this example, the=SCHEMAX= title box is turned on for the schematic plot.

Rc

470 ohm

Rf

390 ohm

Re

4.7 ohm

(2)

SINGLE(1) (2)DARLING(1)

Rf

360 ohm

CE_CE(1) (2)

Rin

50 ohm

Rc

470 ohm

Rf

680 ohm

Re

240 ohm

Rb

120 ohm

CE_CC(1) (2)Rin

50 ohm

Rout

50 ohm

Rc2

470 ohm

Rc1

470 ohm

Re

4.7 ohm

Rc

470 ohm

Rf

360 ohm

Rb

33 ohm

Ro

43 ohm

CONTRACT NO.

DWN

ENGR

CHK

PROD

APVD

APVD

Eagleware Corporation

A 10001 ESIZE DWG NO. REV

SHEET 1 OF 1

WINDOWSINGLE(50)GPH S21 10 20GPH S12 -60 0SMH S11SMH S22FREQSWP 100 1000 19

WINDOWDARLING(50)GPH S21 10 20GPH S12 -60 0SMH S11SMH S22FREQSWP 100 1000 19

WINDOWCE_CC(50)GPH S21 10 20GPH S12 -60 0SMH S11SMH S22FREQSWP 100 1000 19

WINDOWCE_CE(50)GPH S21 10 20GPH S12 -60 0SMH S11SMH S22FREQSWP 100 1000 19

140 Examples

Examples 141

EXAMPLE 11 - UHFVCO.SCH

This is a UHF negative resistance oscillator designed bythe synthesis program =OSCILLATOR=. It tunes from788 to 912 MHz. The graph on the left is the resistanceand reactance looking through the transmission line/ var-actor resonator. If the resistance is negative, when the leftside of the resonator is grounded, the circuit will oscillateat the frequency where the net reactance is zero. Thegraph on the right plots the input return loss on a Smithchart. The normalizing impedance of the Smith chart is-50 ohms so negative input resistance plots inside thecircumference of the chart.

The solid traces are for a tuning varactor capacitance of2.8 pF (oscillation at 912 MHz) and the dashed traces arewith a capacitance of 8 pF (oscillation at 788 MHz).

Please refer to Oscillator Design and Computer Simula-tion for additional information on oscillator design.

NegR(1)

TL

?120 ohm?40°

Ct

?8 pF

Rt

4700 ohm

Estimated min/max tuningcapacitor values:2.4933/8 pF

If you use an inductor for the

28.146 nH.

Power dissipated in Re:768 mW

Cc

470 pF

R1

2700 ohm V-

R2

3300 ohm

T-line, try a value of

Ce

1.5 pF

2N3866

(2)

Re

120 ohm

Le

82 nH

WINDOWNegR(-50,-1e+06)GPH RIN -50 50GPH XIN -50 50SMH C11SMH P11FREQSWP 788 912 101

142 Examples

Examples 143

EXAMPLE 12 - STABILTY.SCH

This example illustrates stabilitycircles and designing an ampli-fier for stability. The first step isto examine the stability charac-teristics of the selected active de-vice before adding additionalcircuitry. Stability should be ex-amined over as broad a frequencyrange as possible, and not justover the range desired for the am-plifier.

Shown here are the input and output plane stabilitycircles for an HP/Avantek AT41586 bipolar transistorbiased at 8 volts and 25 mA. The shaded regions of theSmith chart represent regions of instability. To insurestability, the impedance presented to the device at itsinput terminal should avoid the shaded region of the inputplane stability circles. Similar conditions should be satis-fied at the output. In this case, since the circles labeled“1" represent the lowest frequency and since the top halfof the Smith chart is inductive, stability is enhanced byinsuring that the device is capacitively terminated at lowfrequencies. Therefore, we will use a series capacitor atthe input and output with the smallest value which doesnot disturb the desired amplifier. To further enhancestability, resistors to RF ground are added at the input andoutput. These will also be a part of the bias scheme.

These capacitors and resistors are evident in the sche-matic shown on the next page. The microstrip tee andtransmission line models are added to account for thephysical structure which is necessary to add the resistorsto the amplifier. The remaining microstrip models com-prise the matching networks which were optimized for10dB of gain and best flatness.

144 Examples

DEVICE(1) (2)W=86

L=?300

W=86

L=?530

18 pF 18 pF

Rb

470 ohm

Rc

470 ohm

W=86

L=100

W=86

L=100

W=86

L=?635

W=86

L=165

Examples 145

The results after optimization of the lengths of lines in theinput and output matching networks are shown in the=SuperStar= screen shown above. Notice that the entireSmith chart region, which represents any possible passiveload, is stable for both the input and output. Also noticethat the sweep range for the amplifier gain and match isfrom 2000 to 2800 MHz, but the sweep range for thestability analysis is from 100 to 6000 MHz, the entirerange for which S-parameter data was available. Thelayout after resolution of the rubber band lines is givenbelow.

WINDOWDEVICE(50)GPH S21 0 15SMH S11SMH S22FREQSWP 2000 2800 17OPT2000 2800 S21=10WINDOWDEVICE(50)SMH SB1SMH SB2MARKER100 600 1400 5300 100 1800 4200 6000FREQSWP 100 6000 60

146 Examples

Examples 147

EXAMPLE 13 - TL_COUPL.CKT/SCH

Common but puzzling components used in HF throughUHF circuits are broadband transformers and couplers.They are hybrid mode devices which operate as magnetictransformers at low frequencies and as coupled transmis-sion lines at high frequencies.

In this example, the coupler is simulated assuming themagnetic transformer mode. The equation block is usedto tune the coupling value. We specify the primary turnsand the equation block calculates the closest integer sec-ondary turns. The analysis provides insight which iselusive without simulation; the optimum unused porttermination resistance isn’t equal to Zo and capacitanceimproves the return loss.

The solid curves depict results with a terminating resis-tance of 50 ohms and a nil capacitor. The dashed curvesare with 39 ohms and 1.2 pF. Using tune, you will discoverthe optimum R and C are functions of the coupling valueand whether the through or coupled port is optimized.

COUPLER(1)

(2)

X2

Lsec nH

Lpri nH

K=.99X1

Lpri nH

Lsec nH

K=.99 R

R1 ohmC

C1 pF

(3)

148 Examples

EQUATER1=?50C1=?.01Lpri=100Lcoup=?7Na=?5Nb=Na*SQR(10^(Lcoup/10))Nb=FIX(Nb)Lsec=Lpri*Nb*Nb/Na/Na

WINDOWCOUPLER(50)GPH S21 -10 0GPH S31 -10 0SMH S22 -10FREQSWD 50 900 25

Examples 149

EXAMPLE 14 - FILTLOSS.SCH

This example illustrates the effect of finite component Q(unloaded Q) on the loss of bandpass filters. The filter isa 6th order Chebyshev filter with a shunt-C coupled seriesresonator topology; however, the concepts studied in thisexample apply to bandpass filters in general.

The solid traces for the graph on the left in the =Super-Star= output screen are with inductor Q of 550. CapacitorQ is very high. The dashed traces are with an inductorunloaded Q of 50. The 3-D window on the right depictsS21 with inductor unloaded Q of 550 at the back and 50at the front. Notice that with lower unloaded Q, thepassband insertion loss increases, passband ripple van-ishs and the response becomes more rounded.

Using the marker system, it was determined that as theunloaded Q is reduced from 550 to 50 the midband inser-tion loss increased by 5.34 dB, the insertion loss at thelower corner increased by 8.32 dB and the insertion lossat 700 MHz in the lower stopband increased by 0.36 dB.

The window inset in the lower portion of the screen dis-plays the group delay of the filter. It is interesting to note

FILTER(1)

L1

10 nH

L2

10 nH

C5

36 pF

L3

10 nH

C7

36 pF

L4

10 nH

C9

36 pF

L5

10 nH

C11

36 pF

L6

10 nH

C13

27 pF

L7

10 nH

C15

9 pF

(2)C8

4.03 pF

C6

4.03 pF

C10

4.03 pF

C4

4.2 pF

C12

4.2 pF

C2

5.83 pF

C14

5.83 pF

C3

27 pF

C1

9 pF

150 Examples

that the shape of the group delay corresponds to the excessinsertion loss introduced by finite unloaded Q.

Loss is proportional to the ratio of the filter loaded Q tocomponent unloaded-Q. Decreasing component Q andincreasing filter loaded Q (decreasing the bandwidth) bothincrease insertion loss.

EQUATEQC=1e6QL=?550

WINDOWFILTER(50,50)GPH S21 -60 0GPH S11 -30 0MARKER700 805 945 1050 700 805 945 1050FREQSWP 700 1050 141OPT700 735 S21<-50805 945 S11<-151015 1050 S21<-60

Examples 151

EXAMPLE 15 - TEM_OSC.SCH

This example is a high-stability, low-phase noise oscillatordesigned by =OSCILLATOR=. It uses a coaxial resonatorand a low-cost MMIC amplifier. This example illustratesthe ability of =SuperStar= to plot oscillator loaded Q andthe voltage across its resonator.

The coaxial resonator is a silver-plated ceramic block, nowpopular for use in filters and oscillators. A dielectricconstant of 30 shortens the required resonator length inair from 2.63 inches to 0.48 inches. The dielectric materialadds little loss because conductor loss predominates. Theresonator after loading by the coupling capacitors andtuning varactors is just under one-quarter wavelength.

The solid responses above are with coupling capacitors of1.5 pF. The dashed responses are with these capacitorsreduced to 0.75 pF. The open loop gain and phase areshown on the left. When the loop is closed, the circuit

Loop(1)

Resonant Frequency:1120.92 MHz

MAR3

Path Inductance

Bypass

1500 pFLd

?5.3 nH

V+

Rd

120 ohm

Cc

?1.5 pF

CLI

A=35

B=132.38

L=480.61

Cv pF

Cv pF

Lp

2 nH

Rt

10000 ohm

Cc

?1.5 pF

(2)

(3)

152 Examples

oscillates at the phase zero crossing if there is gain margin(Barkhausen’s criteria). Refer to Oscillator Design andComputer Simulation for discussion of non-linear effects.

The middle graph displays the cascade loaded Q, criticalfor oscillator phase noise performance. On the right is E21at node 3. This acts as a voltage probe since the terminat-ing impedance of this “port” is set very high. With thesmaller coupling capacitors and higher Q, the voltage atnode 3 is 16.4 times the voltage at the input to the MAR3.

EQUATECv=?3.43WINDOWLoop(50,50,1E12)GPH S21 0 12GPH P21 -180 180GPH GD[S21] 0 25MARKER788 850 874.8 912 788 850 874.8 912FREQSWP 788 912 101

WINDOWLoop(50,50,1E12)GPH MAG[E31] 0 30MARKER788 850 874.8 912 788 825.2 874.8 912FREQSWP 788 912 101

Examples 153

EXAMPLE 16 - AMPNOISE.SCH

This example of low-noise amplifier design is based on anarticle by Rob Lefebvre published in the March/April 1997issue of Applied Microwave and Wireless magazine. It is

C1

3.3

pF

(2)

LNA

(1)

TL1

W=

70

L=15

0

TL2

W=

40

L=10

0T

L3

W=

10

L=17

5

TL7

W=

40

L=27

5T

L8

W=

10

L=17

5C4

3.3

pF

R1

51 o

hmR

2

51 o

hm

TL1

0

W=

70

L=15

0

TL4

W=

100

L=17

5

TL9

W=

100

L=15

0

TL6

W=

40

L=90

TL1

4

W=

70

L=75

TL5

W=

40

L=60

Q1

Q1

(2)

DE

VIC

E(1

)

154 Examples

a 9.5 to 10 GHz LNA using an HP/Avantek 10135 GaAsFET.

The amplifier schematic includes an extra FET with onlythe viaholes to ground the FET source leads. This portionof the schematic was added to display the noise circles ofthe FET which are shown in the upper right of the =Su-perStar= output screen. The center of the device noisecircles is the impedance which should be presented to thedevice to acheive the best noise figure for the amplifier.

WINDOWLNA(50)GPH S21 -10 10GPH NFD 0 2SMH S11 -8SMH S22 -8FREQSWP 9000 10000 26OPT9000 10000 S21>6 S22<-12 NFD<1@1E1

WINDOWLNA(50)SMH NCIFREQSWP 9000 10000 11

WINDOWDEVICE(50)SMH NCIFREQSWP 9000 10000 11

Examples 155

This is the impedance seen looking toward the source atthe input to the device.

Narrowband low-noise amplifier design is more straight-forward than broadband design: 1) The device is stabi-lized with source inductance and or shunt resistors at thedevice input and output, 2) the input network is designedto present the correct impedance to the device and 3) theoutput network is designed for maximum gain.

For broadband design the concept is the same. However,presenting the correct impedance to the device across theband and a flat gain requires balancing multiple goals.This is best accomplished using a modern simulator suchas =SuperStar= to optimize all of the requirements simul-taneously. The short arc inside the first noise circle is thelocus of impedances versus frequency which should bepresented to the FET. For even broader bandwidth, the=MATCH= synthesis program can be used to find a net-work which presents near optimum impedance to thedevice over the entire band.

Shown on the lower right are the noise circles of theamplifier with the input network present. Notice that thecenter of the optimum noise arc passes through the centerof the Smith chart. This indicates that the input networkhas been optimized so that at the middle of the frequencyband a 50 ohm source will provide the optimum noiseperformance. This is verified by examining the noisefigure versus frequency plot on the left in the =SuperStar=output screen. The gain flatness was acheived by optimi-zation of the output matching network. Better outputreturn loss could have been acheived by optimizing formatch instead of gain flatness. The match at the inputfalls where it must because the input network is optimizedfor best noise and not best match.

The layout given here was created by importing into thedesktop publishing system a WMF file exported by =LAY-

156 Examples

OUT=. =LAYOUT= also exports AutoCad DXF, HPGLand optimized GERBER 274D/X files.

Examples 157

EXAMPLE 17 - TEM_FILT.SCH

This example illustrates the design of a narrowband UHFfilter using popular dielectric-loaded coaxial resonators.It also illustrates how to use =SuperStar= to sweep acomponent parameter on the horizontal (independentaxis) where the frequency would normally be swept.

When shorted at one end, a quarter-wavelength coaxialresonator behaves like a parallel L-C resonator. To designthis filter, start with a top-C coupled filter topology in=FILTER=. A 6th order 0.1 dB Chebyshev with a lowercutoff frequency of 900 MHz and an upper cutoff of 918MHz is designed. This filter is shown as the top schematicin the figure below.

FILTER(1)

C1

0.99598 pF

C3

0.23903 pF

C5

0.18016 pF

C7

0.17331 pF

C9

0.18016 pF

C11

0.23903 pF

C13

0.99598 pF

(2)

A=Ri

Ro

B=L1

A=Ri

Ro

B=L1

A=Ri

Ro

B=L2

A=Ri

Ro

B=L2

A=Ri

Ro

B=L3

A=Ri

Ro

B=L3

ORIG(1)

L1

2 nH

C2

14.177 pF

L2

2 nH

C4

14.917 pF

C5

0.17872 pF

L3

2 nH

C6

14.982 pF

C7

0.17193 pF

L4

2 nH

C8

14.982 pF

C9

0.17872 pF

L5

2 nH

C10

14.917 pF

L6

2 nH

C12

14.177 pF

(2)C1

.99 pF

C11

0.23711 pF

C3

0.23711 pF

C13

.99 pF

EQUATERo=?1000Ri=0.392*RoL1=502.653L2=515.3095L3=516.4593

WINDOWFILTER(50,50)GPH S21 -50 0GPH S11 -20 0GPH DLY 0 250FREQSWP 886.5 931.5 101

WINDOWFILTER(50,50)GPH S21 -10 0FREQPRM Ro 1e-3 1000 21DIS 909

158 Examples

An advantaged of the top-C coupled topology is that allinductors are identical and the value is user selectable. Touse a coaxial resonator, the inductor value which is en-tered is determined by the Zo of the coaxial resonator bythe following expression from HF Filter Design and Com-puter Simulation:

L=0.2026*Zo/Fo

With a center frequency of 909 MHz and a coaxial resona-tor Zo of 9 ohms, the inductance is 2 nH.

To design a filter using coaxial resonators, each parallelL-C resonator is replaced with the coaxial line (CLI) modelin =SuperStar=. The substrate was edited with the follow-ing parameters added: dielectric constant 38.6, loss tan-gent 1E-4, rho relative to copper 0.92, metalizationthickness 1 mil, roughness 0.05 mils, units 0.0254 (thissets the units to mils) and height 62 mils (height is thesubstrate thickness which has no significance in coax).

Examples 159

Next the lengths of the CLI models is adjusted for bestresponse. Taking advantage of symmetry reduces thenumber of unique lengths to tune from 6 to 3.

Notice in the text portion of the schematic that the coaxialresonator inner radius, Ri, is set equal to 0.392 times theouter radius, Ro. In this way the outer radius can be tunedwithout changing the Zo of the resonator.

The solid traces in the =SuperStar= graphs on the leftshow the response with a coaxial radius of 1000 mils. Thedashed responses are with a radius of 75 mils. Notice thefilter design is unchanged except the insertion loss in-creases significantly. This illustrates how component un-loaded Q increases with increased volume. The secret togood component Q is volume, whether the reactor is atranmission line or a lumped inductor.

Another capability of =SuperStar= further illustrates theloss versus volume relationship. In the graph on the farright, the horizontal scale is a sweep of the resonator outerradius from 1E-3 to 1000 mils. The insertion loss, S21, isplotted at the midband frequency of 909 MHz. The PRM1E-3 1000 21 line in the text portion of the schematic filesteps the radius in 21 steps which is every 50 mils. Theline DIS 909 below the PRM line sets the analysis fre-quency for the radius sweep.

160 Examples

Examples 161

EXAMPLE 18 - MATCHANT.SCH

This example illustrates the dipole antenna model in=SuperStar= and the =MATCH= synthesis program. Thesimple schematic in the upper right of the figure belowuses the built-in =SuperStar= dipole antenna to model theinput impedance of a dipole antenna which is 66 feet intotal length (20116 mm). The diameter of the antennaelements is 2" for a length to diameter ratio of 400. Thismodel was entered in =SuperStar= which was used toexport one-port S-parameter data from the File menu byselecting Write S-parameter data.

Next, the =MATCH= program was used to synthesize thematching network. In =MATCH=, the source was speci-fied as 50 ohms and the load was specified as theMATCHANT.S1P file written by =SuperStar=. A 3rd or-der psuedo-lowpass matching network was selected and

DIPOLE(1)

DIPOLE

MATCH(1)

L1

17689.6 nH

C1

545.34 pF

L2

5048.6 nH

C2

4794.9 pF

L3

28824.5 nH(2)

WINDOWMATCH(50,matchant.s1p)GPH V11SMH S11FREQSWP 3.5 3.6 21

WINDOWDIPOLE(50)DSP RE[I11] IM[I11] V11FREQSWP 3.5 3.6 21

162 Examples

=MATCH= generated the network shown in the sche-matic. The resulting responses are given above. Theantenna is approximately one-eigth wavelength long andis very capacitive. As shown in the tabular window on theright, the original VSWR is over 600 to 1. After matching,the VSWR is under 2 to 1 over the bandwidth from 3.5 to3.6 MHz.

Examples 163

EXAMPLE 19 - ARRYDRV.SCH

Shown below is the schematic for a transmission linematch and phasing network to drive a 3-element phasedarray of loop antennas for receiving. Each loop has aterminal impedance of 560 ohms in series with 4700 nH.Although =SuperStar= handles complex terminations, inthis case we simply placed 4700 nH inductors at theoutput of the driver.

4700 nH

(4)

4700 nH

(2)

4700 nH

(3)

Z4 ohm

L4°

ARRAY(1)

Z4 ohm

L4°

Z4 ohm

L4°

Z4 ohm

L4°

Z2 ohm

L2°

Z2 ohm

L2°

EQUATEL4=?109.7L2=?235.5Z4=300Z2=75

WINDOWARRAY(50,560)GPH S21 -10 0GPH S41 -10 0GPH P21 -225 225GPH P41 -225 225FREQSWP 3 4 21MARKERS3 3.5 3.5 4 3 3.5 3.5 4

OPT3.4 3.6 S21=-3.01 S41=-6.02 P21=0P41=0

WINDOWARRAY(50,560)GPH S11 -20 0FREQSWP 3 4 21MARKERS3 3.5 3.5 4 3 3.5 3.5 4OPT3.4 3.6 S11<-12

164 Examples

In order to produce low sidelobes, it is desired to drive thearray with a binomial amplitude distribution; the centerelement should be driven with twice the amplitude of theend elements. For maximum broadside gain all elementsshould be driven in phase.

Results after optimization are given above. On the leftS21 to the center element and S41 to an end element aregiven. The center plot shows the phases are within about20 degrees. The right plot gives the input return loss.

Examples 165

EXAMPLE 20 - USERMODL.SCH

This example illustrates the creation of a user model. Thecrystal oscillator shown below was synthesized using the=OSCILLATOR= program. To pull the oscillation fre-quency the varactor network to the right of the crystal wasadded. We will create a model for a varactor diode so thatthe frequency versus tuning voltage can be studied.

The capacitance of the varactor versus the tuning voltageis given by the expression: Cv=Co/(1+Vt/0.7)^Gamma

Vt is the varactor reverse tuning voltage. Co is the capaci-tance at Vt=0. Gamma is the power of the C vs V curvewhich is controlled by the varactor doping profile. It istypically 0.5 for abrupt varactors.

V+

Rc

470 ohm

Rf

47000 ohm

R

270 ohmLoop(1)

C1

180 pF

C2

270 pF

XTL

2N5179

(2)

470 pF

Rb

1000 ohm

47000 nH

?5

WINDOWLoop(270,270)GPH S21 0 20GPH P21 -225 225SMH S11SMH S22FREQSWP 10.00 10.01 101

166 Examples

There are parasitics associated with the varactor. Theschematic shown below depicts the series loss resistancewhich results in finite varactor Q. Package capacitanceand package inductance are shown as Cp and Lp.

To create a new usermodel, from the Editmenu in =SCHEMAX=select “Start ModelEditor”. The openingscreen looks like aregular =SCHEMAX= screen. To create a model:

1) Use the same techniques you would use to draw a circuitschematic to draw a schematic of the model. If a compo-nent value is a constant, simply enter the value in thatcomponent’s dialog box. If a value is computed by equa-tions or is to be passed as a parameter in the model, chooseand enter a variable name in the dialog box field.

2) From the File menu, select Edit Model Parameters. Byrepeatedly selecting Add, enter the parameters which willbe passed to the model. A sample for the varactor is givenhere. Some of these parameters are used directly in thedialog boxes of ele-ments (Lp and Cp)and others (Vt, Co, Qand gamma) and areused in the equationsection where the fi-nal element valuesare computed.

3) If equations areused in a model,press F8 and enterthe varactor equa-tions listed in thesample Equation

Examples 167

Text Editor window shownhere.

4) Select Save Model As tosave the model. Put it in anew file with the name VAR-ACTOR.

5) From the =SCHEMAX= Edit menu select “Edit UserToolbars”. Click on Add Button to add a component buttonin the =SCHEMAX= program. Here the name VAR waschosen. Next click Add Entry to select a model name anda schematic symbol to use in =SCHEMAX=.

Here the series resistance, Rs, is computed from the var-actor Q which is typically specified at 4 volts bias and 50MHz. In this way the model finds the effective Q at thedesired tuning voltage and operating frequencies.

The oscillator open loop cascade gain and phase are shownin the sample =SuperStar= screen for tuning voltages of0 and 9 volts. Also shown in the View Variables windoware the varactor model parameters computed by equa-tions.

168 Examples

Examples 169

EXAMPLE 21 - DISHAL.SCH

This example illustrates a tuning technique for coupledresonator filters. Tuning multiple section filters is oftena frustrating experience, and in high volume production,it is costly. In the June, 1952, issue of Electonic Commu-nications, Dishal published “Alignment and Adjustment ofSynchronously Tuned Multiple-Resonant-Circuit Filters.”The method tunes filters in a single pass. Although notexact, it requires very little final adjustment.

Given below is the schematic for a 900-980 MHz, 5th orderChebyshev bandpass filter realized in microstrip on 50 milthick Arlon 450 board. This filter was designed using the=M/FILTER= synthesis program.

FILTER(1)W=WI

H=LI

W=WOUT

H=LOUT

(2)

(3)

C3 pF C4 pF C5 pFC1 pF C2 pF

EQUATEH=50S1=90S2=118S3=S2S4=S1W=90WI=90LI=100WOUT=90LOUT=100L1=252VIAR=40VIAT=0.15

L2=593.569C1=?3.358C2=?3.318C3=?3.304C4=?3.318C5=?3.358WINDOWFILTER(50,50,1E12)GPH S21 -50 0GPH S11 -30 0FREQSWP 840 1040 101WINDOWFILTER(50,50,1E12)

GPH S31 -120 -70FREQSWP 840 1040 101MARKERS840 900 940 980

170 Examples

The technique involves coupling very loosely into the firstresonator. In =SuperStar=, a third port with a terminat-ing impedance of 1E12 ohms is added and the response ofS31 is plotted. In production, a probe is placed in thevacinity of, but not contacting, the first resonator.

The capacitor in the second resonator is shorted with asmall clip. In =SuperStar=, C2 is set to 1E6. The pro-ceedure begins by tuning the first capacitor until theresponse of S31 peaks at the center frequency. This isshown below at the upper left.

Next, the shorting clip is moved to C3 and the secondcapacitor, C2, is tuned for a dip midband as shown in thesecond figure. It is not necessary to retune C1. Next, theshorting clip is moved to C4 and C3 is tuned for a peak atmidband as shown in the upper right. This procedure isrepeated until C5 is tuned. The response after tuning C5is given last. However, C5 is best tuned by looking at thefinal response of the filter.

Examples 171

In the =SuperStar= screen above, the solid traces on theright are the filter transmission and reflection responseswith carefully optimized capacitor values. The dashedresponses are with the capacitors tuned using Dishal’stechnique without any further tuning. Notice that thefrequency is slightly low, but otherwise the tuning is veryaccurate. Before beginning production tuning, by dupli-cating the procedure in =SuperStar=, it is possible todetermine the frequencies at each step to tune for im-proved single-pass performance.

172 Examples

Chapter 12

Element Reference

UNITS


Resistance ohmsInductance nanohenriesCapacitance picofaradsConductance mhosFrequency megahertzDelay nanosecondsLength (elec) degreesLength (phys) mils or millimeters

CIRCUIT BLOCK REFERENCE

The following list is for quick and easy reference of ele-ment codes. The first line specifies the format of the circuitblock line for each code. The second line gives a descrip-tion of the element. An alphabetical list containing de-tailed descriptions of codes follows this list.

RLC MODELS

CAP n1 n2 C= Qc= Name=capacitor

IND n1 n2 L= Ql= Name=inductor

PLC n1 n2 L= C= Ql= Qc= Name=parallel inductor capacitor

PFC n1 n2 Frequency= C= Qc= Name=parallel resonator, frequency & capacitor

PFL n1 n2 Frequency= L= Ql= Name=parallel resonator, frequency & inductor

PRC n1 n2 R= C= Qc= Name=parallel resistor and capacitor network

PRL n1 n2 R= L= Ql= Name=parallel resistor and inductor network

PRX n1 n2 R= L= C= Ql= Qc= Name=parallel resistor inductor capacitor

RES n1 n2 R= Name=resistor

SFC n1 n2 Frequency= C= Qc= Name=series resonator, frequency & capacitor

SFL n1 n2 Frequency= L= Ql= Name=series resonator, frequency & inductor

SLC n1 n2 L= C= Ql= Qc= Name=series inductor capacitor

SRC n1 n2 R= C= Qc= Name=series resistor and capicitor network

SRL n1 n2 R= L= Ql= Name=series resistor and inductor network

SRX n1 n2 R= L= C= Ql= Qc= Name=series resistor inductor capacitor

EXACT MODELS

CIR3 n1 n2 n3 Z= Name=circulator

DELAY n1 n2 n3 T= Z= Name=time delay

GAIN n1 n2 n3 A= S= F= Name=gain

174 Element Reference

GYR n1 n2 n3 n4 Ratio= Name=gyrator

ISOLATOR n1 n2 n3 Z= Name=isolator

MUI n1 n2 n3 n4 L1= L2= K= Name=mutually coupled inductors (transformer)

PHASE n1 n2 n3 A= S= F= Z= Name=phase shift

TRF n1 n2 n3 n4 Option={TR|IM} Primary=Secondary= [Condition=] Name=ideal transformer

TRFCT n1 n2 n3 n4 n5 P= S1= S2= Name=ideal tapped transformer

TRANSMISSION LINES & WIRES

CPL n1 n2 n3 n4 Zoe= Zoo= Length= Koe=Koo= Ae= Ao= Frequency= Name=coupled lines, electrical parameters

CPNx n1 n2... n(x) Zo= k1= k2=... k(0.5x-1)=Length=Koe= Koo= [Ae= Ao= Frequency=]multiple coupled lines, electrical parameters,# of lines=0.5x

RCLIN n1 n2 R= C= L= Name=RC line

RIBBON n1 n2 W= T= L= RH= Name=ribbon wire

TLE n1 n2 Zo= Length= Frequency=Attenuation= Name=transmission line, electrical parameters

TLE4 n1 n2 n3 n4 Zo= Length= Frequency=Attenuation= Name=four terminal transmission line, electrical parameters

Element Reference 175

TLP n1 n2 Zo= Length= Keff= Attenuation=Frequency= Name=transmission line, physical parameters

TLP4 n1 n2 n3 n4 Zo= Length= Keff=Attenuation= Frequency= Name=four terminal transmission line, physical parameters

TLRLDC n1 n2 R= L= C= LEN= Name=distortionless TEM line

TLRLGC n1 n2 R= L= G= C= Name=uniform TEM line

TLX n1 n2 R1= R2= L= K= RPUL= GPUL= Name=exponential TEM line

TRFRUTH n1 n2 n3 N= AL= Z= L= F=transmission line transformer (Ruthroff transformer)

WIRE n1 n2 D= L= RH= Name=wire

LUMPED ELEMENT APPROXIMATIONS

AIRIND1 n1 n2 N= D= L= WD= RHO= Name=single layer air-core solenoid

DIPOLE n1 LEN= LD= Name=dipole antenna

MONOPOLE n1 LEN= LR= Name=monopole antenna

PIN n1 n2 CP= LS= RS= CE= CJ= CD= CI= RJ= RI=Name=PIN diode

SPIND n1 n2 DI= DO= W= S= T= RHO= Name=spiral inductor, no ground plane

TFC n1 n2 W= L= T= ER= RHO= TAND= Name=thin film capacitor

TFR n1 n2 W= L= RS= Name=thin film resistor


TORIND n1 n2 N= AL= RS= QC= FQ= Name=toroidal inductor

DEVICES

ABC n1 n2 n3 AR= AI= BR= BI= CR= CI= DR= DI=ABCD parameters

BIP n1 n2 n3 RBe= RCe= Gm= RBb=CBe= CC= Name=bipolar transistor

CCC n1 n2 n3 RIN= ROUT= BETA= Name=current controlled current source

CCV n1 n2 n3 RIN= ROUT= TR= Name=current controlled voltage source

FET n1 n2 n3 RI= GD= GM= RG= CGs=CDg= RS= CSd= To= Name=FET transistor

ONE n1 n2 Filename= Name=read one-port data file for active or passive devices

OPA n1 n2 n3 RIn= ROut= Gdc= Frequency= Name=operational amplifier

SPA n1 n2 n3 Z= MAG11= ANG11= MAG21= MAG12=ANG12= MAG22= ANG22=S-parameters

TWO n1 n2 n3 Filename= Name=read two-port data file for active or passive devices

THR n1 n2 n3 n4 Filename= Name=read three-port data file for active or passive devices

FOU n1 n2 n3 n4 n5 Filename= Name=read four-port data file for active or passive devices

NPOx n1 n2...nx Filename= Name=read n-port data file for active or passive devices

VCC n1 n2 n3 RIn= ROut= Transconductance= Name=voltage controlled current source


VCV n1 n2 n3 RIN= ROUT= MU= Name=voltage controlled voltage source

PHYSICAL TRANSMISSION LINES ANDDISCONTINUITIES

CEN n1 n2 A= B= Spacing= Name=coaxial end

CGA n1 n2 A = B= Gap= Name=coaxial gap

CLI n1 n2 A= B= Length= Name=coaxial line

CLI4 n1 n2 n3 n4 A= B= Length= Name=four terminal coaxial line

CST n1 n2 Option={IN|OUT} ANarrow=BNarrow= AWide= BWide= Name=coaxial step

MBN n1 n2 Option={CH|SQ} Width= Height= Name=microstrip bend

MCNx n1 n2....n(x) Width= s1= s2=... s(0.5x-1)=Height= Length=multiple coupled microstrip lines, # lines = 0.5x

MCP n1 n2 n3 n4 Width= Spacing= Height=Length= Name=microstrip coupled line

MCR n1 n2 n3 n4 WThru= WCross= Height= Name=microstrip cross

MCURVE n1 n2 W= ANG= RAD= Name=microstrip curve

MEN n1 n2 Width= Height= Name=microstrip end

MGA n1 n2 Width= Gap= Height= Name=microstrip gap


MIDCAP n1 n2 W= G= GE= L= N= Name=microstrip interdigital capacitor

MLI n1 n2 Width= Height= Length= Name=microstrip line

MRIND n1 n2 N= L1= L2= W= S= Name=microstrip rectangular inductor

MRS n1 n2 Radius= Phi= Width= Height= Name=microstrip radial stub

MSPIND n1 n2 DI= DO= W= S= Name=microstrip spiral inductor

MST n1 n2 Option={AS|SY} NARrow= Wide=Height= Name =microstrip step

MTAPER n1 n2 W1= W2= L= Name=microstrip tapered line

MTE n1 n2 n3 WThru= WStub= Height= Name=microstrip tee junction

MVH n1 n2 Radius= Height= Thickness= Name=microstrip via hole to ground

RCNx n1 n2....n(x) Diameter= s1= s2=...s(0.5x-1)= Height= Length=

multiple coupled slablines, # lines = 0.5x

RCP n1 n2 n3 n4 Diameter= Spacing=Height= Length= Name=coupled slabline

RLI n1 n2 Diameter= Height= Length= Name=slabline (rod between ground planes)

SBN n1 n2 Width= Height= Angle= Name=stripline bend

SCNx n1 n2....n(x) Width= s1= s2=... s(0.5x-1)=Height= Length=multiple coupled striplines, # lines = 0.5x


SCP n1 n2 n3 n4 Width= Spacing= Height=Length= Name=stripline coupled line

SEN n1 n2 Width= Height= Name=stripline end

SGA n1 n2 Width= Gap= Height= Name=stripline gap

SLI n1 n2 Width= Height= Length= Name=stripline

SSP n1 n2 Narrow= Wide= Height= Name=stripline step

STE n1 n2 n3 WThru= WStub= Height= Name=stripline tee junction

SUB Er= TAnd= RHo= TMet= ROugh= Units= Name=substrate description for physical models

WAD n1 n2 Width= Height= Zo= Name=waveguide adapter

WLI n1 n2 Width= Height= Length= Name=rectangular waveguide

XTL n1 n2 Rs= Lm= CM= CO= Name=piezoelectric resonator


=SuperStar= CODES

Subsequent sections in this chapter contain informationon element codes, output window specifications, and fre-quency codes available in =SuperStar=.

Each section contains a format description. The format ofthis description is:

• Words in capital letters must be entered as shown.

• Select one item from a list within curly, { }, brackets.

• Words in square brackets, [ ], are optional values. A valueor option is inserted, if needed.

For element codes:

• The picture of a button refers to which =SCHEMAX= groupcontains the element.

• Nodes, such as n1, n2, etc. are replaced with the nodenumber of your choice.

• Values are preceded with a label followed by an equalssign. You have three options

(a) Use the maximum label, the equals sign, and thevalue (Frequency=250).

(b) Use an abbreviated label of any length butwith the letters in the same order, the equals sign,and the value (Freq=250).

(c) Just type the value (250). This is not recommendedfor new users.

• Option codes give choices within curly, { }, brackets.Select one item and type the two letter code.

• Finally, you may name your component by typing Name=followed by the chosen part name (Name=CAP1).

For all nonelement codes:

• Words in lower case are replaced with a choice.

• Words in parentheses are replaced with a numeric value.


It is possible to use negative values in some codes, such asnegative resistors, inductors and capacitors. This is help-ful for analysis of some special type networks. For thisreason, unusual component values have not been trappedout by the program. This does place a certain responsibil-ity for caution by the user while writing circuit files.

In some cases, where unusual values are known to causepossible math exception errors in =SuperStar=, a warninghas been placed in the description for that code. Anexample is coupling coefficients equal to one for MUI.


ABC

ABCD parameters.

Format:ABC 1 2 0 AR=-.5 AI=.5 BR=1 BI=-.2 CR=.1 CI=.3 DR=.5 &DI=-.6

Parameters:AR = Real portion of A.AI = Imaginary portion of A.BR = Real portion of B.BI = Imaginary portion of B.CR = Real portion of C.CI = Imaginary portion of C.DR = Real portion of D.DI = Imaginary portion of D.Name = Component name (optional)

Example:ABC 1 2 0 AR=-.5 AI=.5 BR=1 BI=-.2 CR=.1 CI=.3& DR=.5 DI=-.6

Touchstone Translation:None

Default SPICE Translation:None

1 2

3


AIRIND1

Single-layer air-core solenoid.

Format:AIRIND1 n1 n2 N= D= L= WD= RHO= [NAME=]

Parameters:N = Number of turnsD = Diameter of form (mm)L = Length (mm)WD = Diameter of wire(mm)RHO = Resistivity of wire relative to that of copperName = Component name (optional)

Example:AIRIND1 1 2 N=7 D=5.08 L=11.43 WD=1.143 RHO=1

Range:L>N*WD

Circuit model consists of series R-L shunted by parallel C.Inductance formula is from Wheeler, given by Miller[39].

Use of elliptic functions removes D/L limitations. Resis-tance and capacitance formulas are due to Medhurst [40].

Touchstone Translation:AIRIND1 1 2 N= D= L= WD= RHO=


1 2


BIP

Bipolar transistor model.

Format:BIP n1 n2 n3 RBE= RCe= Gm= RBB= CBe= CC=[Name=]

Parameters:RBe = Intrinsic-base emitter resistanceRCe = Collector-emitter resistanceGm = Transconductance in mhos. It is negative for

common emitter bipolar transistorsRBb = Base spreading resistanceCBe = Intrinsic-base emitter capacitance (pF)CC = Collector-base feedback capacitance (pF)Name = Component name (optional)

Example:BIP 1 3 4 RBB=1250 RCE=50000 Gm=-0.05 RBB=250& CBE=15 CC=1

BIP models a bipolar transistor using a voltage controlledcurrent source plus additional components. The BIP codeis based on the common emitter hybrid-pi model [8].

Typical parameters for a low power, low frequency, NPNbipolar transistor are:

RBe 1250 ohms RCe 50,000 ohmsGm -0.05 mhos RBb 250 ohmsCBe 15 pF CC 1 pF

Some of the parameters are related to the emitter current,beta and Ft via simple expressions. First, the emitter

1

2

3

1

2

3


diffusion resistance, a function of the emitter current, isfound.

where kT/q = 25.7mV at 25oC. Then:

RBe = (1 + beta)ReGm = beta/[(1 + beta)Re]CBe = 1/[2pi*Ft*Re]

Modeling attempts to describe a complex physical processvia a simple equivalent electrical circuit. The result isonly approximate, and the errors tend to increase withfrequency. Measured device data is more accurate. How-ever, modeling is useful at lower frequencies and for spe-cial simulation purposes.


Default SPICE Translation:None (User may specify a SPICE subcircuit or library model.)

RekT

qIe=

RBB ohm

CBE pF

CC pF

n3

n1 n2

RBE ohm RCE ohmGm


CAP

Capacitor with optional Q.

Format:CAP n1 n2 C= [Qc=] [Name=]

Parameters:C = Capacitance (pF)Qc = Q of the capacitor (optional, defaults to 1 million)Name = Component name (optional)

Examples:CAP 1 2 C=22CAP 3 0 C=470 Q=300 N=C1

Q is modeled as constant with frequency. It may be speci-fied higher or lower than the default value.

Touchstone Translation:CAP n1 n2 C=CAPQ n1 n2 C= Q= F=1 MOD=3

Default SPICE Translation:C1_NAME n1 n2 C pFWarning: Q is not modeled in SPICE.

1 2


CCC

Current-controlled current source.

Format:CCC n1 n2 n3 RIN= ROUT= BETA= [Name=]

Parameters:RIN = Input resistance (ohms)ROUT = Output resistance (ohms)BETA = Current gain (dimensionless)Name = Component name (optional)

Example:CCC 1 2 0 RIN=1E-6 ROUT=1E6 BETA=1

Touchstone Translation:CCCS n1 n2 n3 n3 M=BETA A=0 R1=RIN R2=ROUTF=0 T=0


1 2

3


CCV

Current-controlled voltage source.

Format:CCV n1 n2 n3 RIN= ROUT= TR= [Name=]

Parameters:RIN = Input resistance (ohms)ROUT = Output resistance (ohms)TR = Transresistance (ohms)Name = Component name (optional)

Example:CCV 1 2 0 RIN=1E-6 ROUT=1E-6 TR=100

Touchstone Translation:CCVS n1 n2 n3 n3 M=TR A=0 R1=RIN R2=ROUT F=0T=0


1 2

3


CEN

Coaxial open end.

Format:CEN n1 n2 A= B= Spacing= [Name=]

Parameters:A = Center conductor radiusB = Inner radius of outer conductorSpacing = Distance from end of the inner conductor to a

closed endName = Component name (optional)

Example:CEN 1 0 A=100 B=1000 S=50

Range:wavelength > (B-A) > spacing

n2 is normally zero (ground). Substrate characteristicsand units must be established in a previous SUB call. Thecoaxial end is modeled as an effective shunt capacitor. The=SuperStar= model is based on the work of Green [9, 10].The modeled capacitance is within 5% for the specifiedrange. The error increases with increasing spacing, how-ever, the capacitance is also decreasing and is less signifi-cant. The model is intended for use with small spacingswhere the capacitance is significant.



1


CGA

Coaxial center conductor gap.

Format:CGA n1 n2 A= B= Gap= [Name=]

Parameters:A = Center conductor radiusB = Inner radius of outer conductorGap = Distance between the ends of the inner conductorsName = Component name (optional)

Example:CGA 1 2 A=100 B=1000 G=20

Range:5 > A/B >1.1110.30 >Gap/B >0.05

The substrate characteristics and dimensional units mustbe established in a previous call to SUB.

The coaxial gap is modeled as a shunt capacitor, seriescapacitor and shunt capacitor in cascade. Capacitors arefound by fitting closed form expressions to data given byGreen [9, 10]. The modeled capacitances are within ap-proximately 5% over the parameter range, but degraderapidly outside the range.



1 2


CIR3

Ideal three-port circulator.

Format:CIR3 n1 n2 n3 Z= [Name=]

Parameters:Z = Reference resistance, Zo (ohms)

Examples:CIR3 1 2 0 Z=50

Touchstone Translation:CIR3 n1 n2 n3


1 2

3


CLI

Coaxial transmission line.

Format:CLI n1 n2 A= B= Length= [Name=]

Parameters:A = Center conductor radiusB = Inner radius of outer conductorLength= Physical length of transmission lineName = Component name (optional)

Example:CLI 1 0 A=100 B=1000 L=3500

Range:Range: operation frequency is below TE01 cutoff

The substrate characteristics and dimensional units mustbe established in a previous call to SUB. The model isidentical to the coaxial line model in =TLINE= from Eagle-ware.

Touchstone Translation:COAX n1 n2 0 0 DI= DO= L= ER= TAND= RHO=


See also:SUB, CEN, CGA, CLI4 and CST.

1 2


CLI4

Four terminal coaxial line from a physical description.

Format:CLI4 n1 n2 n3 n4 A= B= Length= [Name=]

Parameters:A = Center conductor radiusB = Inner radius of outer conductorLength= Physical length of transmission lineName = Component name (optional)

Range:Operation frequency must be below TE01 cutoff

The coaxial transmission line is connected as shown in thediagram below. The substrate characteristics and dimen-sional units must be established in a previous call to SUB.The model is identical to the coaxial line model in=TLINE= from Eagleware.

Touchstone Translation:COAX n1 n2 n3 n4 DI= DO= L= ER= TAND= RHO=


1 2

3 4


CPL

Coupled line four-port based on an electrical description.

Format:CPL n1 n2 n3 n4 ZOE= ZOO= Length= KOE= KOO=

[AE= AO= Frequency=] [Name=]

Parameters:ZOE = Even mode characteristic impedanceZOO = Odd mode characteristic impedanceLength= Physical length (mm)KOE = Even mode effective dielectric constantKOO = Odd mode effective dielectric constantAE = Even mode loss (optional) (dB/meter)AO = Odd mode loss (optional) (dB/meter)Freq. = Frequency for loss (MHz) (optional)Name = Component name (optional)

Example:CPL 1 0 2 0 ZOE=55 ZOO=45 L=50 KOE=1.73& KOO=1.60

The letters OE and OO represent the even and odd modesrespectively. The loss model increases as the square rootof the sweep frequency. If the losses are not specified thelines are lossless and the frequency should not be speci-fied.

Touchstone Translation:CLINP n1 n2 n3 n4 ZE= ZO= L= KE= AE= AO=


1

2 3

4


CPNx

Multiple coupled transmission lines usinfg an electricalmodel. The number of lines is 0.5x.

Format:CPNx n1 n2...n(x) Zo= K1= K2=...K(0.5x-1)= Length=

KOE= KOO= [AE= AO= Frequency=] [Name=]

Parameters:Zo = Characteristic impedance of all lines (see formula)

(All lines must be equal impedance)K# = Coupling coefficients (see formula)Length= Physical length (mm)KOE = Even mode effective dielectric constantKOO = Odd mode effective dielectric constantAE = Even mode loss (optional)AO = Odd mode loss (optional)Freq. = Frequency for loss (MHz) (optional)Name = Component name (optional)

Example:CPN8 1 2 3 4 5 6 7 8 Zo=50 K1=.03 K2=.01 K3=.03& L=200 Koe=1.73 Koo=1.60

The number of nodes is x. The coupling coefficients are k1through k(0.5x-1). Their definition is:

1 2 3 4 5

678910

KZ Z

Z Zoe oo

oe oo=

−b gb g2

ZZ Z

Z Zooe oo

oe oo=

+2b g

b g


The letters OE and OO represent the even and odd modesrespectively. The loss model increases as the square rootof the sweep frequency. If the losses are not specified thelines are lossless and the frequency should not be speci-fied.

This model is a significant convenience for analyzingcombline, interdigital and other multiple coupled linestructures. The multiple coupled line model is based onan exact wire-line equivalent of cascaded coupled pairs oflines (CPL).



Example with n=8n1

n8

k1 k2 k3

n2

n7

n3

n6

n4

L(mm)

n5


CST

Coaxial step in the inner or outer conductor of coax.

Format:CST n1 n2 Option={IN|OU} ANarrow= BNarrow=

AWide= BWide= [Name=]

Parameters:Option = IN for inner step, OU for outer stepANarrow = Input Center conductor radius (at n1)BNarrow = Input Inner radius of outer conductor (at n1)AWide = Output Center conductor radius (at n2)BWide = Output Inner radius of outer conductor (at n2)Name = Component name (optional)

Example:CST 1 2 O=IN AN=20 BN=100 AW=50 BW=100

Range:For an inner conductor step:

1 > α > 0.016 > τ >1α = (BNarrow -AWide)/(BNarrow - ANarrow)τ = BNarrow/ANarrow

For an outer conductor step0.7 > α > 0.016 > τ >1.5α = (BNarrow - ANarrow)/(BWide - ANarrow)τ = BWide/AWide

Option IN indicates a step in the inner conductor and OUindicates a step in the outer conductor. The dielectric andconductor characteristics and dimensional units must be

1 2


established in a previous call to SUB. A step in bothconductors is modeled by cascading two steps.

NOTE: In optimization, =SuperStar= will automaticallyadjust if the “narrow”values are greater than the “wide”values.

The coaxial step is modeled as an effective shunt capacitor.The =SuperStar= model is based on Somlo [11] and Davis[12]. The modeled effective capacitance is within approxi-mately 0.2 pF/BNarrow (meters) for inner conductor stepsand 0.4 pF/BNarrow (meters) for outer conductor steps.




DELAY

Ideal delay.

Format:DELAY n1 n2 n3 T= Z= [Name=]

Parameters:T = Delay (nanoseconds)Z = Reference resistance, Zo (ohms)Name = Component name (optional)

Examples:DELAY 1 2 0 T=1 Z=50

Touchstone Translation:DELAY n1 n2 T=


1 2

3


DIPOLE

Dipole antenna of finite thickness.

Format:DIPOLE n1 LEN= LD= [Name=]

Parameters:LEN = Total length of dipole (mm)LD = Ratio of total length to diameter (dimensionless)Name = Component name (optional)

Examples:DIPOLE 1 LEN=150 LD=100

Obtains input impedance referenced to input terminals,not to current maximum.

Based on Balanis [41] section 7.3.2 valid for any length.

Touchstone Translation:DIPOLE n1 n2 L=LEN LD=


1


FET

Field effect transistor model.

Format:FET n1 n2 n3 RI= GD= GM= RG=

CGs= CDg= RS= CSd= To= [Name=]

Example:FET 1 2 3 RI=2 GD=200 GM=-0.07 RG=2.5 CGS=.25& CDG=0.10 RS=2 CSD=0.10 TO=1E-6 NAME=ATF101

FET models a junction or insulated-gate FET using a VCCsource plus additional components. FET is based on acommon source, voltage controlled current source model[13]. Typical values for several GaAsFETs are given in[14]. For example, the ATF-101XX at 2V and 20mA is

RI 2 ohms 1/GD 200 ohmsGM -0.07 mhos RG 2.5 ohmsCGs 0.25 pF CDg 0.10 pFRS 2 ohms CSd 0.10 pFTo 1E-6 nanoseconds

1

2

3

1

2

3

CGs pF

CDg pF

Rs ohm

CSd pF

RI ohmGD ohm

n3

RG ohmn1 n2

Gate Drain

Source


The Wolf and Avantek models place the drain-source ca-pacitance in slightly different positions. Also, the Avantekmodel includes information on chip and bond-wire induc-tances. The Wolf model includes a shunt R-L network atthe input. In critical applications, these differences arereadily incorporated in =SuperStar= by externally addingthe appropriate components to the FET model.

Modeling describes a complex physical process via a sim-ple equivalent electrical circuit. The result is approxi-mate, and the error tends to increase with frequency.Measured device data is more accurate. Models are bestfor lower frequencies and special purposes.

Equations which reduce the model to exact equivalent Yor other parameters for use in a simulation program arequite complex. Authors (including Wolf in his derivationof Y-parameters) often make simplifying assumptions tothe equations. This is not the case in =SuperStar=, wherethe program exactly matches the model schematic. There-fore, you may experience small differences in the responsecomputed by =SuperStar= and other simulation pro-grams. The differences are generally insignificant in re-lation to errors associated with the modeling process.


Default SPICE Translation:.SUBCKT X$NAME 1 2 3

R_g 1 4 rgC_dg 4 2 cdg pFC_Gs 4 5 cgs pFR_i 5 6 riR_s 3 6 rsR_d 2 6 rd pFC_sd 2 3 csd pFG_Gm 6 2 5 6 Gm

.ENDS X$NAME


FOU

Creates a four-port by reading data from a disk file.

Format:FOU n1 n2 n3 n4 n5 Filename= [Name=]

Parameters:Filename = Full path and filename containing dataName = Component name (optional)

Example:FOU 1 2 3 4 0 F=MCROSS.S4P

The data is stored in standard sequential ASCII files. Forexample, the format for four-port S-Parameter data is:

The data can be all on one line, or, for readability, can bebroken into multiple lines as shown above. The frequencyof data stored in the data file need not match the frequen-cies of a run. =SuperStar= will interpolate or extrapolatethe data to obtain the parameters at the run frequencies.

Touchstone Translation:S4PA n1 n2 n3 n4 filename(Note: Node n5 must be ground)


1 2 3 4 5

Freq S S S S S S S S

S S S S S S S S

S S S S S S S S

S S S S S S S S

11 11 21 21 31 31 41 41

12 12 22 22 32 32 42 42

13 13 23 23 33 33 43 43

14 14 24 24 34 34 44 44

∠ ∠ ∠ ∠∠ ∠ ∠ ∠∠ ∠ ∠ ∠∠ ∠ ∠ ∠


GAIN

Ideal gain block.

Format:GAIN n1 n2 n3 A= S= F= [Name=]

Parameters:A = Flat gain for 0<FREQ<F (dB)S = Gain slope for FREQ>=F (dB/octave)F = Frequency at which gain slope starts (MHz)Name = Component name (optional)

Examples:GAIN 1 2 0 A=6 S=6 F=4

Touchstone Translation:GAIN n1 n2 A= S= F=


1 2

3


GYR

Gyrator.

Format:GYR n1 n2 n3 n4 Ratio= [Name=]

Parameters:Ratio = Gyrator ratioName = Component name (optional)

Example:GYR 1 2 3 4 R=6

The gyrator network is connected to nodes as indicated inthe diagram below. The gyrator may be considered asback-to-back current controlled voltage sources,

V1 =R * I2V2 = -R * I1

where R is the gyrator ratio. S-parameters are:

C11 = C22 = (r*r-1)/(r*r+1)C21 = -C12 = -2r/(r*r+1)

where

r = R/Zo.

Touchstone Translation:GYR n1 n2 R=


1 2

3 4


IND

Inductor with optional Q.

Format:IND n1 n2 L= [Ql=] [Name=]

Parameters:L = Inductance (nanohenries)Ql = Q of the inductor (optional, defaults to 1 million)Name = Component name (optional)

Example:IND 1 2 L=33 Q=100

Q is modeled as constant with frequency and may bespecified higher or lower than the default value.

Touchstone Translation:IND n1 n2 L=INDQ n1 n2 L= Q= F=1 MOD=3

Default SPICE Translation:L1_NAME n1 n2 LnHWarning: Q is not modeled in SPICE.

1 2


ISOLATOR

Ideal isolator.

Format:ISOLATOR n1 n2 n3 Z= [Name=]

Parameters:Z = Reference resistance, Zo (ohms)Name = Component name (optional)

Example:ISOLATOR 1 2 0 Z=50

Touchstone Translation:ISOLATOR n1 n2


1 2

3


MBN

Microstrip bend.

Format:MBN n1 n2 Option={CH|SQ} Width= [Height=] [Name=]

Parameters:Option = CH (chamfered corner) or SQ (square corner)Width = Width of stripHeight = Height of substrate (optional, may be specified inSUB)Name = Component name (optional)

Example:MBN 2 3 O=CH W=80

Range:15000/H(mm) > Freq(MHz)6 >W/H >0.213 >Er >2

90o square and chamfered corners are available. Thesubstrate characteristics and dimensional units must beestablished in a previous SUB. The bend model is a seriesL, shunt C, series L tee. The capacitance error is small.The inductance error is greater for W/H > 1. Predictedresonator frequencies are generally within 0.3% [15].

Touchstone Translation:MBEND2 n1 n2 W= (Chamfered)MCORN n1 n2 W= (Square)


1

2

WW

SQUARE CHAMFER

W W


MCNx

Multiple coupled microstrip lines. The number of lines is0.5x.

Format:MCNx n1 n2..n(x) Width= S1= S2=..S(0.5x-1)= [Height=]

Length= [Name=]

Parameters:Width = Width of strips (all are equal widths)S# = Edge-to-edge separations (see figure below)Height = Height of substrate (opt., may be specified in SUB)Length = Physical length of linesName = Component name (optional)

Example:MCN8 1 2 3 4 5 6 7 8 W=100 S1=15 S2=25 S3=15 L=800

Range:See MCP

The number of nodes is x. The spacing between the farleft and the next line is s1. The spacing between the farright and the preceding line is s(0.5x-1).

This model is convenient for analyzing combline, interdigi-tal and other multiple coupled line structures. Multiplecoupled microstrip is based on an exact wire-line equiva-lent of cascaded coupled pairs of microstrip line. There-fore, full-wave based analytical models is utilized.

1 2 3 4 5

678910


Touchstone Translation:MACLIN3 n1 n2 n3 n4 n5 n6 W1= W2= W3= S1= S2= L=(Only available for MCN6)


Example with n=8n1

n8

s1w w ww s2 s3

n2

n7

n3

n6

n4

L

n5


MCP

Two coupled microstrip lines.

Format:MCP n1 n2 n3 n4 Width= Spacing= [Height=]

Length= [Name=]

Parameters:Width = Width of strips (both are equal widths)Spacing = Edge-to-edge separation of the strips.Height = Height of substrate (opt., may be specified in SUB)Length = Physical length of linesName = Component name (optional)

Example:MCP 1 0 2 0 W=80 S=15 L=1000

Range:30000/Height(mm) > Freq(MHz) 18 > Er > 110 > Width/Height > 0.1 10 > Spacing/Height > 0.1metal thickness < 0.1*Height and < 0.2*Spacing

The substrate characteristics and the units of dimensionsare established in a previous call to SUB. The accuracy isgenerally within 1% for the indicated parameter ranges,provided a cover is sufficiently removed [16,17,18]. Ade-quate cover spacings are determined using =TLINE= fromEagleware.

Touchstone Translation:MCLIN n1 n2 n3 n4 W= S= L=


1

2 3

4


MCR

Microstrip cross.

Format:MCR n1 n2 n3 n4 WThru= WCross= [Height=] [Name= ]

Parameters:WThru = Width of thru lines (at nodes 1 and 2)WCross = Width of cross line (at nodes 3 and 4)Height = Height of substrate (opt., may be specified in SUB)Name = Component name (optional)

Example:MCR 1 2 3 4 WT=100 WC=400

Range:15000/Height(mm) > Freq(MHz)18 > Er > 110 > WThru / Height > 0.1WCross < 10 * WThru

The discontinuity model used for MCR was developed byEagleware and verified with field simulation. The modelincludes phase shift effects as well as junction discontinu-ity effects. The accuracy and limits are similar to the MTEmodel.

Touchstone Translation:MCROS n1 n3 n2 n4 W1= W2= W3=W1 W4=W2


1 2

3

4

WCross

WThrun2n1

n4

n3


MCURVE

Curved bend in microstrip.

Format:MCURVE n1 n2 W= ANG= RAD= [Name=]

Parameters:W = Width of microstrip lineANG = Angle of bend (degrees)RAD = Radius of bend measured to center of lineName = Component name (optional)

Examples:MCURVE 1 2 W=25 ANG=90 RAD=50

Range:RAD>2*W

See MLI for microstrip restrictions. Equivalent length ofmicrostrip line determined by ANG and RAD modified toaccount for curvature as per Weisshaar and Tripathi [42].

Touchstone Translation:MCURVE n1 n2 W= ANG= RAD=


1 2

W

RAD

ANG


MEN

Microstrip open end.

Format:MEN n1 n2 Width= [Height=] [Name=]

Parameters:Width = Width of stripHeight = Height of substrate (opt., may be specified in SUB)Name = Component name (optional)

Example:MEN 3 0 W=80

Range:15000/Height(mm) > Frequency(MHz)50 > Er > 2Width / Height > 0.2

Node n2 is normally grounded (node 0). The substratecharacteristics and dimensional units must be establishedin a previous. The accuracy is generally within 4% for theindicated parameter ranges [19][10], provided a cover issufficiently removed.

Touchstone Translation:MLEF n1 W= L=0


1 2

W


MGA

Microstrip gap.

Format:MGA n1 n2 Width= Gap= [Height=] [Name=]

Parameters:Width = Width of stripGap = Spacing between the ends of the stripsHeight = Height of substrate (opt., may be specified in SUB)Name = Component name (optional)

Example:MGA 1 2 W=80 G=8

Range:15000/Height(mm) > Freq(MHz) 15 > Er > 2.02 > Width / Height > 0.5 1 > Gap / Width > 0.1

The substrate characteristics must be established in aprevious SUB. The accuracy is generally within 7% for theindicated parameter ranges.The end is modeled as a shuntC, series C, shunt C pi network [20][10].

Touchstone Translation:MGAP n1 n2 W= S=


1 2

G

WW


MIDCAP

Interdigitated capacitor in microstrip.

Format:MIDCAP n1 n2 L= W= G= GE= N= [Name=]

Parameters:L = Length of fingersW = Width of each conductor (finger)G = Space between conductors (fingers)GE = Space at end of conductor (finger)N = Number of fingersName = Component name (optional)

Examples:MIDCAP 1 2 W=0.005 G=0.005 GE=0.001 L=0.1 N=5

Range:N>=3

See MLI for usual mi-crostrip restrictions.Capacitance only with-out parasitics. Capaci-tance is computedusing the formulas ofGevorgian, et.al. [43].

Touchstone Translation:MICAP1 n1 n2 W= G= GE= L= NP=N/2


1 2

W

G

n1

n2

L

GE


MLI

Microstrip line from a physical description.

Format:MLI n1 n2 Width= [Height=] Length= [Name=]

Parameters:Width = Width of stripHeight = Height of substrate (opt., may be specified in SUB)Length= Length of lineName = Component name (optional)

Example:MLI 1 2 W=80 L=200

Range:30000/Height(mm) > Frequency(MHz)128 > Er > 1100 > Width/Height > 0.01metal thickness < Height and < Width

The substrate characteristics and dimensional units mustbe established in a previous call to SUB. The accuracy isgenerally within 1% for the indicated parameter ranges,provided a cover is sufficiently removed. Adequate coverspacings are determined using =TLINE= from Eagleware.This model [21,22] is identical to the =TLINE= model andincludes dispersion.

Touchstone Translation:MLIN n1 n2 W= L=


1 2


MONOPOLE

Monopole above a ground plane.

Format:MONOPOLE n1 LEN= LR= [Name=]

Parameters:LEN = Length of monopole not including image (mm)LR = Length as defined above, LEN, divided by radius (dimen-sionless)Name = Component name (optional)

Examples:MONOPOLE 1 L=75 LR=100

Range:

Calculates input impedance at input terminals, not refer-enced to current maximum. Based on Balanis [41] section7.3.2 valid for any length.

Touchstone Translation:MONOPOLE n1 L= LR=


1


MRIND

Planar rectangular inductor in microstrip.

Format:MRIND n1 n2 L1= L2= L3 W= S= N [Name=]

Parameters:L1 = Length of first inside segmentL2 = Length of second inside segmentL3 = Length of third inside segmentW = Width of conductorsS = Space between conductorsN = Number of turns (does not need to be an integer)Name = Component name (optional)

Example:MRIND 1 2 L1=20 L2=50 L3=50 W=5 S=5 N=7.16

Range:

N can be any positive real value. Cascade of elements eachone modeling one segment for which the inductance (self,

1 2

W

S

L1

L2

n1

n2

L3

W+S

n=1.75

n=2n=2.25

n=1.875


mutual , and image due to ground plane) is computedusing the formulas of Grover [44]. Capacitane is com-puted from the parallel plate capacitane of microstriplines and the fringing capacitance using the formulationof Smith [45]. Loss resistance is based on skin-effect.Other references used are Greenhouse [49] and Krafcsikand Dawson [52]. The overall calculation is valid up to thevicinity of the first resonance.

For a square inductor, make L2=L3.




MRS

Microstrip radial stub.

Format:MRS n1 n2 Radius= Phi= Width= [Height=] [Name=]

Parameters:Radius= Radius of stub (R in diagram below)Phi = Stub width in degrees (j in diagram)Width = Width of the stub base (W on diagram)Height = Height of substrate (opt., may be specified in SUB)Name = Component name (optional)

Example:MRS 1 2 R=100 Phi=30 W=20

Range:15000/Height(mm) > Frequency(MHz)

The stub is connected parallel to the transmission path.The digram below illustrates the geometry of the radialstub [23][24]. The ends of the feed lines are referenced tothe center of the radial stub. Note that the penetrationdepth may exceed the width of the microstrip feed line.The base width and the penetration depth, P, are relatedby the formula .

Touchstone Translation:MRSTUB n1 WI= L= ANG=


1 2

W P= × ×2 2tanϕ

W

R

Penetration

j


MSPIND

Planar spiral inductor in microstrip (includes groundplane).

Format:MSPIND n1 n2 RI= W= S= N= [Name=]

Parameters:RI = Inside radius, meassured to edge of conductorW = Width of conductorS = Space between conductorsN = Number of turns (does not need to be an integer)Name = Component name (optional)

Example:MSPIND 1 2 RI=100 W=5 S=5 N=3.3

Lumped PI model consisting of shunt C, series R-L, shuntC all paralleled by a capacitor. Inductance is calculatedusing the formulas of Remke and Burdick [46]. Capaci-tance based on Smith [45]. Resistance is d-c or skin-effectresistance, whichever is greater.

1 2

n1

n2

W

S

RI

Planar ViewPerspective View

Substrate

Metallization

T

Ground Plane


The overall calculation is valid up to near the first reso-nance.

Non-integral turn counts are interpolated from integralamounts and may be slightly less accurate.

Touchstone Translation:MSPIND n1 n2 DI= DO= W= S=



MST

Microstrip step.

Format:MST n1 n2 Option={AS|SY} NARrow= Wide= [Height=]

[NAMe=]

Parameters:Option = AS for asymmetrical step, SY for symmetrical stepNARrow = Line width on the n1 side.Wide = Width on the n2 side.Height = Height of substrate (opt., may be specified in SUB)NAMe = Component name (optional)

Example:MST 1 2 O=SY NAR=100 W=300 NAM=STEP

Range:15000/Height(mm) > Frequency(MHz)10 > Er > 13.5 > Narrow / Wide > 0.28

Use SY for a symmetrical step as pictured. Use AS for anasymmetrical step in which only one edge is discontinuous(not pictured). The substrate characteristics and dimen-sional units must be established in a previous SUB.

1 2

Narrow Wide


NOTE: In optimization, =SuperStar= will automaticallyadjust if the “narrow”values are greater than the “wide”values.

The accuracy is generally within 10% for the indicatedparameter ranges.

The step is modeled as a series L, Shunt C, series L pinetwork. It is based on Benedek and Silvester [20], Farraand Adams [25], Gopinath [26] and Gupta [10].

Touchstone Translation:MSTEP n1 n2 W1= W2= (Symmetrical)None (Asymmetrical)



MTAPER

Linearly tapered line in microstrip.

Format:MTAPER n1 n2 W1= W2= L= [Name=]

Parameters:W1 = Width of line at n1 end (wide on symbol)W2 = Width of line at n2 end (narrow on symbol)L = Length of lineName = Component name (opt.)

Examples:MTAPER 1 2 W1=0.835 W2=0.435 L=5

Range:

See MLI for usual microstrip restrictions. The overalltaper of length L is modeled as a cascade of 10 equi-lengthmicrostrip lines that have widths varying linearly fromW1 to W2.

Touchstone Translation:MTAPER n1 n2 W1= W2= L=


1 2

W1

L

W2n1 n2


MTE

Microstrip tee junction.

Format:MTE n1 n2 n3 WThru= WStub= [Height=] [Name=]

Parameters:WThru= Width of thru lines (at nodes 1 and 2)WStub= Width of stub line (at node 3)Height = Height of substrate (opt., may be specified in SUB)Name = Component name (optional)

Example:MTE 1 2 3 WT=100 WS=400

Range:15000/Height(mm) > Frequency(MHz)10 > WThru / Height > 0.1WStub < 10 * WThru18 > Er > 1

The discontinuity model used for MTE was developed byEagleware and verified with field simulation. MTE in-cludes phase shift effects as well as junction discontinuityeffects. The model is similar to several other proposedmodels with the advantage that phase and stub reflectionare more accurately modeled for a wide range of εr,height,and width ratios. The accuracy decreases with increasingfrequency but is good through 12GHz with Height=50mils. Smaller heights increase the frequency limit.

The reference planes to define the length of connectinglines are the dashed lines in the diagram below.

1 2

3


Touchstone Translation:MTEE n1 n2 n3 W1= W2=W1 W3=


WStub

WThrun2n1

n3


MUI

Two mutually coupled inductors.

Format:MUI n1 n2 n3 n4 L1= L2= K= [Name=]

Parameters:L1 = Inductance of coil between n1 and n2 (nanohenries)L2 = Inductance of coil between n3 and n4 (nanohenries)K = Coefficient of couplingName = Component name (optional)

Example:MUI 1 2 3 4 L1=100 L2=100 K=.999999

A negative value of “K” inverts the phase. MUI models atransformer including winding inductance and coupling.The relationship between K and the mutual inductance is:

WARNING: “K” must not equal 1.

Touchstone Translation:MUC n1 n3 n2 n4 L1= L2= M=

Default SPICE Translation:.SUBCKT X$NAME 1 2 3 4

L_IND1 1 2 L1 nHL_IND2 3 4 L2 nHK_MUI L_IND1 L_IND2 k

.ENDS X$NAME

1

2 3

4

KL

L Lmutual= ⋅1 2


MVH

Microstrip via hole.

Format:MVH n1 n2 Radius= [Height=] [Thickness=] [Name=]

Parameters:Radius = Via hole outside radiusHeight = Height of substrate (opt., may be specified in SUB)Thickness= Thickness of via hole lining (optional)Name = Component name (optional)

Example:MVH 1 0 R=30

Range:15000/Height(mm) > Frequency(MHz)

MVH creates a very low impedance to ground, modeled asa series RL. n2 is normally ground (node 0). If thethickness of the via hole lining is not specified, then theSUB conductor thickness is used. The following diagramshows the MVH reference plane definition [27].

Touchstone Translation:VIA n1 n2 D1= D2=D1 H= T=


1 2

R


NPOn

Creates an n-port network by reading data from a disk file

Format:NPOn n1...n(n+1) Filename= [Name=]


Example:NPO6 1 2 3 4 5 6 0 F=MCROSS.S6P

The data is stored in standard ASCII files. The format forn-port S-Parameter data is:


Touchstone Translation:SnPA n1 n2 ... n(n) filename(Note: Node n(n+1) must be ground)


1 2 3 4 5 6 7 8 9

Freq S S S S S S

S S S S S S

S S S S S S

n n

n n

n n n n nn nn

11 11 21 21 1 1

12 12 22 22 2 2

1 1 2 2

∠ ∠ ∠∠ ∠ ∠

∠ ∠ ∠

L

L

M M M M O M M

L


ONE

Creates a one-port by reading data from a disk file.

Format:ONE n1 n2 Filename= [Name=]


Example:ONE 1 0 F=MRF901.615 N=Q1

The data is stored in standard sequential ASCII files. Oneline of data is a set of data for one frequency. In anS-Parameter file, a typical line might be

500 .64 -23

This line indicates S11=0.64∠−23° at 500 MHz.

The frequency of data stored in the data file need notmatch the frequencies of a run. =SuperStar= will inter-polate or extrapolate the data to obtain the parameters atthe run frequencies.

Touchstone Translation:S1P n1 n2 filename


1 2


OPA

Operational amplifier.

Format:OPA n1 n2 n3 RIn= ROut= Gdc= Frequency= [Name=]

Parameters:RIn = Input resistance (ohms)ROut = Output resistance (ohms)Gdc = Open loop gain (voltage ratio, not in dB) at 0 Hz.Frequency = Open loop unity gain crossover frequency (MHz)Name = Component name (optional)

Example:OPA 1 2 2 RI=1E6 RO=75 G=50000 F=1 Name=U741

Touchstone Translation:OPA n1 n2 n3 0 0 M=GDC A=0 R1=RI R2=RI R3=RO

R4=0 F=F T=0


R_In1 1 0 RinR_In2 2 0 RinR_Out 4 3 RoutE_VCV 4 0 1 2 Gdc

.ENDS X$NANMEWarning: Crossover frequency is not modeled in SPICE.

1

2

3


PFC

Parallel L-C resonator.

Format:PFC n1 n2 Frequency= C= [Ql=] [Qc=] [Name=]

Parameters:C = Capacitance (pF)Ql = Q of the inductor (opt., defaults to 1 million)Qc = Q of the capacitor (opt., defaults to 1 million)Name = Component name (optional)

Example:PFC 1 2 F=88 C=100 Ql=35 Qc=600


This code generates the same network as PLC. However,the frequency and capacitance are specified instead of theinductance and capacitance. This is useful for two rea-sons. First, networks with bandpass and bandstop struc-tures are often ill-behaved for optimization. As the L or Cis changed to adjust the L/C ratio, the frequency is per-turbed. The use of this resonator code can dramaticallyreduce optimization time in many networks, sometimes byas much as an order of magnitude. Secondly, this code iswell suited to tuning or optimizing a response while leav-ing a transmission zero or peak at a desired frequency.

See also:PFL, SFC and SFL.

1 2


PFL

Parallel L-C resonator.

Format:PFL n1 n2 Frequency= L= [Ql=] [Qc=] [Name=]

Parameters:L = Inductance (nH)Ql = Q of the inductor (opt., defaults to 1 million)Qc = Q of the capacitor (opt., defaults to 1 million)Name = Component name (optional)

Example:PFL 1 2 F=88 L=100 Ql=35 Qc=600


This code generates the same network as PLC. However,the frequency and inductance are specified instead of theinductance and capacitance. This is useful for two rea-sons. First, networks with bandpass and bandstop struc-tures are often ill-behaved for optimization. As the L or Cis changed to adjust the L/C ratio, the frequency is per-turbed. The use of this resonator code can dramaticallyreduce optimization time in many networks, sometimes byas much as an order of magnitude. Secondly, this code iswell suited to tuning or optimizing a response while leav-ing a transmission zero or peak at a desired frequency.

See also:PFC, SFC and SFL.

1 2


PHASE

Ideal phase shift, matched input and output.

Format:PHASE n1 n2 n3 A= S= F= Z= [Name=]

Parameters:A = Constant phase shift for 0<FREQ<F (degrees)S = Phase slope for FREQ>F (degrees/octave)F = Frequency for onset of slope (MHz)Z = Reference resistance, Zo (ohms)Name = Component name (optional)

Examples:PHASE 1 2 0 A=45 S=45 F=5 Z=50

These elements can be cascaded to obtain arbitrary phaseresponses.

Touchstone Translation:PHASE n1 n2 A= S= F=


1 2

3


PIN

Circuit model of PIN diode.

Format:PIN n1 n2 CP= LS= RS= CE= CJ= CD= CI= RJ= RI=[Name=]

Parameters:CP = Package capacitance (pF)LS = Series inductance (nH)RS = Series resistance (ohms)CE = Gap capacitance (pF)CJ = Junction capacitance (pF)CD = Diffusion capacitance (pF)CI = I layer capacitance (pF)RJ = Junction resistance (ohms)RI = I layer resistance (ohms)Name = Component name (optional)

Examples:PIN 1 2 CP=0.3 LS=0.3 RS=0.3 CE=0.02 CJ=0.17& CD=0.01 CI=1E6 RJ=1E9 RI=0.01

PIN 1 2 CP=0.3 LS=0.3 RS=0.3 CE=0.02 CJ=10 CD=3& CI=0.25 RJ=0.1 RI=0.5

The first set of values CJ=0.17 ... correspond to a diode inthe off state; the second to a diode in the on state. Theequivalent circuit for the PIN is:

1 2


Touchstone Translation:PIN n1 n2


Rs

Rj

Ri

Cd Cj CeCp

Ci

Ls

n1

n2


PLC

Parallel inductor and capacitor network.

Format:PLC n1 n2 L= C= [Ql=] [Qc=] [Name=]

Parameters:L = Inductance (nH)C = Capacitance (pF)Ql = Q of the inductor (opt., defaults to 1 million)Qc = Q of the capacitor (opt., defaults to 1 million)Name = Component name (optional)

Example:PLC 1 2 L=100 C=22 Ql=35 Qc=600


1 2


PRC

Parallel resistor capacitor network.

Format:PRC n1 n2 R= C= [Qc=] [Name=]

Parameters:R = Resistance (ohms)C = Capacitance (pF)Qc = Q of the capacitor (opt., defaults to 1 million)Name = Component name (optional)

Example:PRC 1 2 R=50 C=22 Qc=600


1 2


PRL

Parallel resistor inductor network.

Format:PRL n1 n2 R= L= [Ql=] [Name=]

Parameters:R = Resistance (ohms)L = Inductance (nH)Ql = Q of the inductor (opt., defaults to 1 million)Name = Component name (optional)

Example:PRL 1 2 R=50 L=100 Ql=35


1 2


PRX

Parallel resistor inductor capacitor network.

Format:PRX n1 n2 R= L= C= [Ql=] [Qc=] [Name=]

Parameters:R = Resistance (ohms)L = Inductance (nH)C = Capacitance (pF)Ql = Q of the inductor (opt., defaults to 1 million)Qc = Q of the capacitor (opt., defaults to 1 million)Name = Component name (optional)

Example:PRX 1 2 R=50 L=100 C=22 Ql=35 Qc=600


1 2


RCLIN

Distributed RC transmission line.

Format:RCLIN n1 n2 R= C= L= [Name=]

Parameters:R = Distributed resistance p.u.l (ohms/mm)C = Distributed capacitance p.u.l. (pF/mm)L = Length (mm)Name = Component name (optional)

Example:RCLIN 1 2 R=0.8 C=0.8 L=12.7

Touchstone Translation:RCLIN n1 n2 R= C= L=


1 2


RCNx

Multiple coupled rods (slabline). The number of lines is0.5x.

Format:RCNx n1 n2...n(x) Dia= S1= S2=...s(0.5x-1)= [Height=]

Length= [Name=]

Parameters:Diameter= Diameter of rods (all are equal diameter)S# = Edge-to-edge separations (see figure below)Height = Ground-to-ground spacing (opt., can be given in

SUB)Length = Physical length of linesName = Component name (optional)

Example:RCN8 1 2 3 4 5 6 7 8 W=200 S1=55 S2=65 S3=55 L=800

Range:See RCP

The number of nodes is x. The edge-to-edge spacing be-tween the far left and the next rod is s1. The spacingbetween the far right and the preceding rod is s(0.5x-1).

This model is a significant convenience for analyzingcombline, interdigital and other multiple coupled rodstructures. The model is based on an exact wire-lineequivalent of cascaded coupled pairs of rods.

1 2 3 4 5

678910




Example with n=8n1

n8

s1D D DD s2 s3

n2

n7

n3

n6

n4

L

n5


RCP

Two coupled round rods centered between flat groundplanes (coupled slabline).

Format:RCP n1 n2 n3 n4 Diameter= Spacing= [Height=]

Length= [Name=]

Parameters:Diameter= Diameter of rods (both are equal diameter)Spacing = Edge-to-edge separation of the rodsHeight = Ground-to-ground spacing (opt., can be given in

SUB)Length = Physical length of linesName = Component name (optional)

Example:RCP 1 0 2 0 D=200 S=300 H=500 L=1200

Range:0.2 < D/H < 0.8S/H > 0.1

The dimensional units and substrate characteristics mustbe defined in a previous SUB. The coupled slabline modelis an Eagleware curve fit to accurate numerical solutiondata [28]. Stracca, et. al., also provide analytical expres-sions but with errors up to 3%. Eagleware expessions arewithin 0.25% of the numeric data for D/H from 0.2 to 0.8and S/H > 0.1.

1

2 3

4




S

n1

n4

n2

n3

DH


RES

Resistor.

Format:RES n1 n2 R= [Name=]

Parameters:R = Resistance (ohms)Name = Component name (optional)

Example:RES 1 2 R=100

R is the resistance in ohms.

Touchstone Translation:RES n1 n2 R=

Default SPICE Translation:R1_NAME n1 n2 R

1 2


RIBBON

Conducting wire of rectangular cross section.

Format:RIBBON n1 n2 W= T= L= RH= [Name=]

Parameters:W = Width of wire (mm)T = Thickness of wire (mm)L = Length of wire (mm)RH = Resistivity of wire relative to that of copperName = Component name (optional)

Example:RIBBON 1 2 W=0.0394 T=0.00394 L=0.394 RH=1

Resistance is d-c resistance or skin effect resistance de-pending upon which is larger.

Range:W>>T

The circuit model is series R-L. The formula for induc-tance is Eq. (7), p. 102 of Greenhouse [49]. The resistanceis based on skin-effect with a correction for current crowd-ing as in Eq. (6.2.2.5), p. 385 of Wadell [50].

Touchstone Translation:RIBBON n1 n2 W= L= RHO=RH


1 2


RLI

Round rod transmission line centered between flat groundplanes (slabline).

Format:RLI n1 n2 Diameter= [Height=] Length= [Name=]

Parameters:Diameter= Rod DiameterHeight = Ground-to-ground spacing (opt., can be given in

SUB)Length = Physical length of lineName = Component name (optional)

Example:RLI 1 2 D=200 H=500 L=1200

The dimensional units and substrate characteristics mustbe defined in a previous SUB. Slabline is particularly wellsuited for applications where a high unloaded Q (low loss)is required. An approximate expression due to Frankelhas been widely used since 1942, but this model is a curvefit to more accurate numerical solution data [28]. Theimpedance is believed to be within a fraction of a percentof the precise value for D/H from 0.10 to 0.90.



1 2

H D


SBN

Stripline bend.

Format:SBN n1 n2 Width= Height= Angle= [Name=]

Parameters:Width = Width of stripHeight = Height of substrate (opt., may be specified in SUB)Angle = Angle of bend in degrees (j in diagram below)Name = Component name (optional)

Example:SBN 1 2 W=100 A=90

Range:1.75 > Width/Height > 0.25

Arbitrary corner angles are supported. The substratecharacteristics and dimensional units must be establishedin a previous SUB.

The errors from measured data demonstrate excellentagreement and suggest a much wider useful parameterrange for bends of 90o or less. The model is a series L,shunt C, series L tee with added strip lines to simulate theadded length of the path [29].

Touchstone Translation:SBEND n1 n2 W= ANG=


1

2

W

Wj


SCNx

Multiple coupled striplines. The number of lines is 0.5x.

Format:SCNx n1 n2...n(x) Width= S1= S2=..S(0.5x-1)= [Height=]

Length= [Name=]

Parameters:Width = Width of strips (all are equal widths)S# = Edge-to-edge separations (see figure below)Height = Height of substrate (opt., may be specified in SUB)Length = Physical length of linesName = Component name (optional)

Example:SCN8 1 2 3 4 5 6 7 8 W=100 S1=15 S2=25 S3=15 L=800

Range:See SCP

The number of nodes is x. The spacing between the farleft and the next line is s1. The spacing between the farright and the preceding line is s(0.5x-1).

This model is a significant convenience for analyzingcombline, interdigital and other multiple coupled linestructures. The model is based on a wire-line equivalentof cascaded coupled pairs of stripline.

1 2 3 4 5

678910




Example with n=8n1

n8

s1w w ww s2 s3

n2

n7

n3

n6

n4

L

n5


SCP

Coupled striplines.

Format:SCP n1 n2 n3 n4 Width= Spacing= [Height=]

Length= [Name=]

Parameters:Width = Width of strips (both are equal width)Spacing = Edge-to-edge separation of the striplines.Height = Height of substrate (opt., may be specified in SUB)Length = Physical length of linesName = Component name (optional)

Example:SCP 1 0 2 0 W=100 S=15 L=800

Range:Width/Height > 0.35 (less restrictive for small metal thickness)0.1 > metal thickness/Height

The substrate characteristics and dimensional units mustbe established in a previous call to SUB.

The model [30,10] is identical to the model in =TLINE=.

Touchstone Translation:SCLIN n1 n2 n3 n4 W= S= L=


1

2 3

4


SEN

Stripline open end.

Format:SEN n1 n2 Width= [Height=] [Name=]

Parameters:Width = Width of stripHeight = Height of substrate (opt., may be specified in SUB)Name = Component name (optional)

Example:MEN 5 0 W=100

Range:2 > Width/Height > 0.1

Node n2 is normally ground (node 0). The substratecharacteristics and dimensional units must be establishedin a previous call to SUB.

The errors from measured data demonstrate excellentagreement and suggest a much wider useful parameterrange [29].

Touchstone Translation:SLEF n1 W= L=0


1 2

W


SFC

Series L-C resonator.

Format:SFC n1 n2 Frequency= C= [Ql=] [Qc=] [Name=]

Parameters:C = Capacitance (pF)Ql = Q of the inductor (opt., defaults to 1 million)Qc = Q of the capacitor (opt., defaults to 1 million)Name = Component name (optional)

Example:SFC 1 2 F=88 C=22 Ql=35 Qc=600


This code generates the same network as SLC. However,the frequency and capacitance are specified instead of theinductance and capacitance. This is useful for two rea-sons. First, networks with bandpass and bandstop struc-tures are often ill-behaved for optimization. As the L or Cis changed to adjust the L/C ratio, the frequency is per-turbed. The use of this resonator code can dramaticallyreduce optimization time in many networks, sometimes byas much as an order of magnitude. Secondly, this code iswell suited to tuning or optimizing a response while leav-ing a transmission zero or peak at a desired frequency.

See also:PFC, PFL, and SFL.

1 2


SFL

Series L-C resonator.

Format:SFL n1 n2 Frequency= L= [Ql=] [Qc=] [Name=]

Parameters:L = Inductance (nH)Ql = Q of the inductor (opt., defaults to 1 million)Qc = Q of the capacitor (opt., defaults to 1 million)Name = Component name (optional)

Example:SFL 1 2 F=88 L=100 Ql=35 Qc=600


This code generates the same network as SLC. However,the frequency and inductance are specified instead of theinductance and capacitance. This is useful for two rea-sons. First, networks with bandpass and bandstop struc-tures are often ill-behaved for optimization. As the L or Cis changed to adjust the L/C ratio, the frequency is per-turbed. The use of this resonator code can dramaticallyreduce optimization time in many networks, sometimes byas much as an order of magnitude. Secondly, this code iswell suited to tuning or optimizing a response while leav-ing a transmission zero or peak at a desired frequency.

See also:PFC, PFL, SFC.

1 2


SGA

Stripline gap.

Format:SGA n1 n2 Width= Gap= [Height=] [Name=]

Parameters:Width = Width of stripGap = Spacing between the ends of the stripsHeight = Height of substrate (opt., may be specified in SUB)Name = Component name (optional)

Example:SGA 1 2 W=100 G=5

The substrate characteristics and dimensional units mustbe established in a previous call to SUB. Height is thethickness of the substrate (ground-to-ground spacing).

Little data is given with respect to the parameter ranges,except that the model accuracy is suspect for high striplineimpedance. The gap model is a shunt L, series C, shunt Lpi. The model is based on Altschuler and Oliner [29].



1 2

G

WW


SLC

Series inductor and capacitor network.

Format:SLC n1 n2 L= C= [Ql=] [Qc=] [Name=]

Parameters:L = Inductance (nH)C = Capacitance (pF)Ql = Q of the inductor (opt., defaults to 1 million)Qc = Q of the capacitor (opt., defaults to 1 million)Name = Component name (optional)

Example:SRL 1 2 L=100 C=22 Ql=35 Qc=600


1 2


SLI

Single strip transmission line between ground planes(Stripline).

Format:SLI n1 n2 Width= [Height=] Length= [Name=]

Parameters:Width = Width of stripHeight = Height of substrate (opt., may be specified in SUB)Length= Physical length of lineName = Component name (opt.)

Example:SLI 1 2 W=100 L=1800

RangeWidth/Height > 0.35 (less restrictive for small metal thickness)0.1 > metal thickness/Height

The substrate characteristics and the dimensional unitsmust be established in a previous call to SUB. Width isthe width of the strip. Height is the thickness of thedielectric substrate (ground-to-ground). Length is thephysical length of the line.

The model [31,32,33,34] is identical to the =TLINE=model.

Touchstone Translation:SLIN n1 n2 W= L=


1 2


SPA

S-parameters.

Format:SPA 1 2 0 Z= MAG11= ANG11= MAG21= ANG21=

MAG12= ANG12= MAG22= ANG22=

Parameters:Z Reference Impedance (Ohms).MAG11 S11 magnitude.ANG11 S11 phase (degrees).MAG21 S21 magnitude.ANG21 S21 phase (degrees).MAG12 S12 magnitude.ANG12 S12 phase (degrees).MAG22 S22 magnitude.ANG22 S22 phase (degrees).Name Component name (optional)

Example:SPA 1 2 0 Z=50 MAG11=.2 ANG11=15 MAG21=2ANG21=90

MAG12=.15 ANG12=-45 MAG22=2 ANG22=90

Touchstone Translation:NONE

Default SPICE Translation:NONE

1 2

3


SPIND

Planar spiral inductor without ground plane.

Format:SPIND n1 n2 RI= W= S= N= T= RHO= [Name=]

Parameters:RI = Inner radius, measured to edge of conductor (mm)W = Width of conductor (mm)S = Space between adjacent conductors (mm)N = Number of turns (does not need to be an integer)T = Thickness of conductorRHO = Resistivity of conductor relative to that of copperName = Component name (optional)

Example:SPIND 1 2 RI=20 W=5 S=5 N=1.6 T=1 RHO=1

Series R-L with inductance (self and mutual) determinedby Remke and Burdick formulas. Resistance is d-c resis-tance or skin-effect resistance, whichever is greater. Thismodel and MSPIND are the same except for the absence

1 2

n1

n2

WS

RI

Planar ViewPerspective View

Substrate

Metallization

T


of capacitive coupling and the image inductance due to theground plane.

Non-integral turn counts are interpolated from integralamounts and may be slightly less accurate.




SRC

Series resistor and capacitor network.

Format:SRC n1 n2 R= C= [Qc=] [Name=]

Parameters:R = Resistance (ohms)C = Capacitance (pF)Qc = Q of the capacitor (opt., defaults to 1 million)Name = Component name (optional)

Example:SRC 1 2 R=50 L=22 Qc=600


1 2


SRL

Series resistor and inductor network.

Format:SRL n1 n2 R= L= [Ql=] [Name=]

Parameters:R = Resistance (ohms)L = Inductance (nH)Ql = Q of the inductor (opt., defaults to 1 million)Name = Component name (optional)

Example:SRL 1 2 R=50 L=100 Ql=35


1 2


SRX

Series resistor, inductor and capacitor network.

Format:SRX n1 n2 R= L= C= [Ql=] [Qc=] [Name=]

Parameters:R = Resistance (ohms)L = Inductance (nH)C = Capacitance (pF)Ql = Q of the inductor (opt., defaults to 1 million)Qc = Q of the capacitor (optional, defaults to 1 million)Name = Component name (optional)

Example:SRX 1 2 R=50 L=100 C=50 Ql=35


1 2


SSP

Stripline step in width.

Format:SSP n1 n2 NARrow= Wide= [Height=] [NAMe=]

Parameters:NARrow = Line width on the n1 side.Wide = Width on the n2 side.Height = Height of substrate (opt., may be specified in SUB)NAMe = Component name (optional)

Example:SSP 1 3 NAR=100 W=300 NAM=STEP

Range:6.6 > Lwidth/Rwidth > 0.15

The substrate characteristics and dimensional units mustbe established in a previous SUB. NOTE: During optimi-zation, =SuperStar= adjusts if the “narrow” values aregreater than the “wide” values.

The errors from measured data demonstrate excellentagreement and suggest a wider useful parameter range.The step model is a short stripline, series reactance, anda short negative-length stripline [29].

Touchstone Translation:SSTEP n1 n2 W1= W2=


1 2

Narrow Wide


STE

Stripline tee junction.

Format:STE n1 n2 n3 WThru= WStub= [Height=] [Name=]

Parameters:WThru= Width of thru lines (at nodes 1 and 2)WStub= Width of stub line (at node 3)Height = Height of substrate (opt., may be specified in SUB)Name = Component name (optional)

Example:STE 1 2 3 WT=100 WS=200

Range:10 > WThru / Height > 0.1 WStub < 10 * WThru.

STE includes phase shift effects as well as junction dis-continuity effects[29].

Touchstone Translation:STEE n1 n2 n3 W1= W2=W1 W3=


1 2

3

WStub

WThrun2n1

n3


SUBDefines substrate properties for physical models whichfollow it.

Format:SUB Er= TAnd= RHo= TMet= ROugh=

Units= [Height=] [Name=]

Parameters:Er = Relative dielectric constantTAnd = Loss tangent of the dielectric materialRHo = Metalization resistivity relative to copper.TMet = Thickness of the strip (Use 0 for coaxial and

waveguide models)ROugh= Metalization roughness. (Increases conductor

losses.)Units = Constant which sets units in physical models.Height = Default height for physical models.Name = Component name (optional)

=SCHEMAX=:Access in substrate menu

Example:SUB Er=2.2 TAND=4e-4 RHO=1 TMet=.71& ROUGH=.055 Units=0.0254 Height=22

This code defines the properties of the materials used toconstruct physical transmission lines and discontinuities.These substrate properties remain in effect for all physicalmodels defined before another SUB code is used.

Typical values for Er are: air=1, teflon=2.1, glass=4.8,alumina=10.

Loss tangent (TAnd) ranges from near zero for air, 2E-4for teflon, to 1E-2 for epoxy glass. Resistivity (RHo) is 1.42for gold, 0.95 for silver, 3.9 for brass, and 52 for stainlesssteel. TAnd is responsible for loss in the dielectric and


nstewart

Text Box

PTFE

nstewart

Text Box

PTFE

RHo for loss in conductors. Units is a constant whichestablishes dimensional units in physical models. It is 1.0for millimeters and 0.0254 for mils(thousanths of an inch).Although other constants may be used, these are the onlyofficially supported dimensions.

Touchstone Translation:SSUB ER= B= T= RHO= (Stripline)MSUB ER= H= T= RHO= RGH= (Microstrip)TAND TAND=



TFC

Thin film capacitor.

Format:TFC n1 n2 W= L= T= ER= RHO= TAND= [Name=]

Parameters:W = Width (mm)L = Length (mm)T = Thickness of dielectric film (mm)ER = Relative dielectric constant of dielectric film (dimension-less)RHO = Resistivity relative to that of copper (dimensionless)TAND = Dielectric loss tangent of dielectric film (dimension-less)Name = Component name (optional)

Example:TFC 1 2 W=10 L=10 T=0.04 ER=2 RHO=1 TAND=0.0001

Series R-C with C equal to parallel plate capacitance ofwidth, length, and thickness with width modified from Wto account for fringing. Resistance based on skin-effectresistance of plate and loss tangent of dielectric.

Touchstone Translation:TFC n1 n2 W= L= T= ER= RHO= TAND=


1 2


TFR

Thin film resistor on dielectric above a ground plane.

Format:TFR n1 n2 W= L= RS= [Name=]

Parameters:W = Width of lineL = Length of lineRS = Surface resistivity (ohms/square)Name = Component name (optional)

Example:TFR 1 2 W=25 L=100 RS=100

Model mkes use of microstrip distributed inductance andcapacitance and series resistance per unit length based onRS.

Range:

See MLI for microstrip restrictions. Distributed R,L,G,Cmodel with L, G, and C determined by microstrip parame-ters and R based on the specified surface resistivity, RS.

Touchstone Translation:TFR n1 n2 W= L= RS= F=0


1 2


THR

Creates a three-port by reading data from a disk file.

Format:THR n1 n2 n3 n4 Filename= [Name=]


Example:THR 1 2 3 0 F=OPAMP.S3P

The data is stored in standard sequential ASCII files. Theformat for S-Parameter data is:


Touchstone Translation:S3PA n1 n2 n3 filename (Note: Node n4 must be ground)


1 2 3 4

Freq S S S S S S

S S S S S S

S S S S S S

11 11 21 21 31 31

12 12 22 22 32 32

13 13 23 23 33 33

∠ ∠ ∠∠ ∠ ∠∠ ∠ ∠


TLE

Transmission line described with electrical parametersand optional loss.

Format:TLE n1 n2 Zo= Length= Frequency=

[Attenuation=] [Name=]

Parameters:Zo = Characteristic impedance (ohms)Length= Electrical length at specified frequency (degrees)Freq. = Frequency for length and loss (MHz)Atten. = Actual loss in dB at the specified frequency. (opt.)Name = Component name (optional)

Example:TLE4 1 2 Z=50 L=90 F=1200

The model for loss is proportional to the square root of thefrequency. For example, if .24 dB of loss is specified at 1200MHz, the loss will be .24Ö2 dB (.34 dB) at 2400 MHz. Thedefault value of loss is 0 dB. Zo is the characteristicimpedance, in ohms, of the transmission line.

Touchstone Translation:TLIN n1 n2 Z= E= F=

Default SPICE Translation:

1 2


TLE4

Four terminal transmission line described with electricalparameters and optional loss.

Format:TLE4 n1 n2 n3 n4 Zo= Length= Frequency=

[Attenuation=] [Name=]

Parameters:Zo = Characteristic impedance (ohms)Length= Electrical length at specified frequency (degrees)Freq. = Frequency for length and loss (MHz)Atten. = Actual loss in dB at the specified frequency. (opt.)Name = Component name (optional)

Example:TLE4 1 2 3 0 Z=50 L=90 F=1200

The model for loss is proportional to the square root of thefrequency. For example, if .24 dB of loss is specified at 1200MHz, the loss will be .24Ö2 dB (.34 dB) at 2400 MHz. Thedefault value of loss is 0 dB.

Touchstone Translation:TLIN4 n1 n2 n3 n4 Z= E= F=


1 2

3 4


TLP

Transmission line described with physical parametersand optional loss.

Format:TLP n1 n2 Zo= Length= Keff=

[Attenuation= Frequency=] [Name=]

Parameters:Zo = Characteristic impedance (ohms)Length= Physical length (millimeters)Keff = Effective dielectric constant.Atten. = Loss in dB/meter at the specified frequency. (opt.)Freq. = Frequency for loss (MHz) (optional)Name = Component name (optional)

Example:TLP 1 2 Z=75 L=200 K=2.2

If the optional loss is specified, the frequency in megahertzfor that loss must be specified. The model for loss isproportional to the square root of the frequency. Thedefault value of loss is 0 dB.

Touchstone Translation:TLINP n1 n2 Z= L= K= A= F=


1 2


TLP4

Four-terminal transmission line described with physicalparameters and optional loss.

Format:TLP4 n1 n2 n3 n4 Zo= Length= Keff=

[Attenuation= Frequency=] [Name=]

Parameters:Zo = Characteristic impedance (ohms)Length= Physical length (millimeters)Keff = Effective dielectric constant.Atten. = Loss in dB/meter at the specified frequency. (opt.)Freq. = Frequency for loss (MHz) (optional)Name = Component name (optional)

Example:TLP4 1 2 3 0 Z=75 L=200 K=2.2

If the optional loss is specified, the frequency in megahertzfor that loss must be specified. The model for loss isproportional to the square root of the frequency. Thedefault value of loss is 0 dB.

Touchstone Translation:TLINP4 n1 n2 n3 n4 Z= L= K= A= F=


1 2

3 4


TLRLDC

Distortionless TEM transmission line.

Format:TLRLDC n1 n2 R= L= C= LEN= [Name=]

Parameters:R = Resistance p.u.l. (ohms/mm)L = Inductance p.u.l (nH/mm)C = Capacitance p.u.l (pF/mm)L = Length (mm)Name = Component name (optional)

Example:TLRLDC 1 2 R=0.05 L=0.005 C=0.002 LEN=50

Shunt conductance p.u.l is calculated automatically sothat R/L=G/C.



1 2


TLRLGC

Uniform TEM transmission line.

Format:TLRLGC n1 n2 R= L= G= C= LEN= [Name=]

Parameters:R = Series resistance p.u.l. (ohms/mm)L = Series inductance p.u.l. (nH/mm)G = Shunt conductance p.u.l. (Siemen/mm)C = Shunt capacitance p.u.l (pF/mm)LEN = Length (mm)Name = Component name (optional)

Example:TLRLGC 1 2 R=0.05 L=0.005 G=1.88E-8 C=0.002 LEN=50



1 2


TLX

Exponential TEM transmission line.

Format:TLX n1 n2 R1= R2= L= K= RPUL GPUL [Name=]

Parameters:R1 = Resistance, (L/C)^1/2 at n1 end (ohms)R2 = Resistance, (L/C)^1/2 at n2 end (ohms)L = Length (mm)K = Effective dielectric constant (dimensionless)RPUL = Series resistance p.u.l. (ohms/mm)GPUL = Shunt conductance p.u.l. (Siemen/mm)Name = Component name (optional)

Example:TLX 1 2 R1=50 R2=200 L=12.7 K=1 RPUL=0 GPUL=0

Exact mathematical solution of TEM L,C line as given byBurrows [47] for characteristic impedance, SQRT(L/C),varying exponentially with length along the line. Loss isincluded as a perturbation.

The exponential taper is calculated automatically usingthe values of R1 and R2.



1 2


TORIND

Toroidal core inductor.

Format:TORIND n1 n2 N= AL= RS= QC= FQ= [Name=]

Parameters:N = Number of turns (dimensionless)AL = Inductance index (nH)RS = Total winding resistance (ohms)QC = Core quality factor (dimensionless)FQ = Reference frequency of QC (MHz)Name = Component name (optional)

Examples:TOROID1 2 N=10 AL=10 RS=5 QC=100 FQ=50

Series R-L in parallel with series R-C. R in series R-L isthe specified resistance RS;L is determined by the numberof turns and the inductance index

L=N^2*AL

C in the series R-C branch is deter-mined by the specified resonancefrequency and the computed valueof L. The core quality factor QCdetermines the series R in the R-Cbranch.

Touchstone Translation:CIND2 n1 n2 N= AL= R=RS Q=QC F=FQ


1 2

n1 n2


TRF

Ideal transformer.

Format:TRF n1 n2 n3 n4 Option={TR|IM} Primary= [Secondary=]

[Condition=] [Name=]

Parameters:Option = TR for turns ratio, IM for impedance ratioPrimary = Number of turns on primary (TR) or primary

impedance (IM)Secondary = Number of turns on secondary (TR) or

sec. impedance (IM). (opt., defaults to 1)Condition = conditioning factor (optional)Name = Component name (optional)

Example:TRF 1 2 0 0 Option=IM P=200 S=50

The turns and impedance are relative. For example, 200and 50 will have the same result as 4 and 1. If an invertingtransformer is desired, primary is negative. An idealtranformer can ill-condition the matrix =SuperStar= mustsolve. This causes the red error bar to illuminate. Toeliminate this problem, certain networks using TRF mayrequire a conditioning factor, typically 0.001 to .1.

Touchstone Translation:XFER n1 n2 n3 n4 N=


1 2

3 4


TRFCT

Ideal transformer with tapped secondary.

Format:TRFCT n1 n2 n3 n4 n5 P= S1= S2 [Name=]

Parameters:P = Number of primary turns(dimensionless)S1 = Number of turns between node 2 & 5 (dimensionless)S2 = Number of turns between 5 & 4 (dimensionless)Name = Component name (optional)

Example:TRFCT 1 2 0 3 0 P=1 S1=2 S2=2

P, S1, and S2 are used to obtain turns ratios. The absolutevalues are immaterial. The ratio is all that matters.



1 2

3 4

5


TRFRUTHTransmission line transformer.

Format:TRFRUTH n1 n2 n3 N= AL= Z= L= F= [Name=]

Parameters:N Number turns (dimensionless)AL Inductance index (nH/turn/turn)Z Characteristic impedance (ohms)L Electrical length at specified frequency (degrees)F Frequency for length (MHz)Name Component name (optional)

Example:TRFRUTH 1 2 3 N=1 AL=1 Z=2 L=45 F=1000

Ruthroff transformer modeled as a transmission line(TLE4) with shunt inductance.

This is an ideal model based on the paper by Ruthroff [51].The shunt inductance is given by:

L = N2 · AL.

Touchstone Translation:XFERRUTH N=N AL=AL Z=Z E=L F=F



TWO

Creates a two-port by reading data from a disk file.

Format:TWO n1 n2 n3 Filename= [Name=]


Example:TWO 1 2 0 Option=SP Zo=50 F=MRF901.615 N=Q1

The data is stored in standard sequential ASCII files. Oneline of data is a set of data for one frequency. In anS-Parameter file, a typical line might be

500 .64 -23 12.5 98 .03 70 .8 -37

The frequency of data stored in the data file need notmatch the frequencies of a run. =SuperStar= will inter-polate or extrapolate the data to obtain the parameters atthe run frequencies.

Touchstone Translation:S2PA n1 n2 n3 filename


1

2

3

1

2

3

1

2

3

1

2

3

1 2

31 2 3


VCC

Voltage controlled current source.

Format:VCC n1 n2 n3 RIn= ROut= Transconductance= [Name=]

Parameters:RIn = Input resistance (ohms)ROut = Output resistance (ohms)Transconductance = Transconductance in mhosName = Component name (optional)

Example:VCC 1 3 0 RI=50 RO=1000 T=1

Range:The input and output resistance must be greater than zero.

Touchstone Translation:VCCS n1 n2 n3 n3 M=T A=0 R1=RIN R2=ROUT F=0 T=0


R_In 3 1 RinR_Out 3 2 RoutG_Gm 3 2 1 3 Gm

.ENDS X$NAME

1 2

3

Rin Rout

Gm


VCV

Voltage-controlled voltage source.

Format:VCV n1 n2 n3 RIN= ROUT= MU= [Name=]

Parameters:RIN = Input resistance (ohms)ROUT = Output resistance (ohms)MU = Voltage gain (dimensionless)Name = Component name (optional)

Example:VCV 1 2 0 RIN=1E6 ROUT=1E-6 MU=1

Touchstone Translation:VCVS n1 n2 n3 n3 M=MU A=0 R1=RIN R2=ROUT F=0T=0

Default SPICE Translation:Done

1 2

3


WAD

Rectangular waveguide-to-TEM adapter.

Format:WAD n1 n2 Width= [Height=] Zo= [Name=]

Parameters:Width = Width of waveguide (A)Height = Height of waveguide (B) (opt., may be given in SUB)Zo = Characteristic impedance of the TEM mode side

(coaxial, microstrip, etc.) of the adapter.Name = Component name (optional)

Example:WAD 1 2 W=100 H=50 Zo=50

The dimensional units must be established by a SUB callanytime before WAD.

Waveguide impedance is frequency dependent.Waveguide-to-TEM adapters transform frequency de-pendent waveguide to constant impedance TEM mode.The WAD code ideally models this transformation. Themodel is based on Marcuvitz [35]. The guide impedanceis the frequency dependent wave impedance of the TE10mode in rectangular guide. The electrical length is zero.



1 2


WIRE

Conducting wire of circular cross section.

Format:WIRE n1 n2 D= L= RH= [Name=]

Parameters:D = Diameter of wire (mm)L = Length of wire (mm)RH = Resistivity relative to that of copperName = Component name (optional)

Example:WIRE 1 2 D=0.0254 L=0.254 RH=1

Touchstone Translation:WIRE n1 n2 D= L= RHO=RH

The circuit model is series R-L. The formula for induc-tance is Eq. (2), p. 101 of Greenhouse [49]. The frequencycorrection term for inductance is based on Grover [44] andEq. (6.2.1.2), p. 383 of Wadell [50]. The resistance is basedon skin-effect.


None

1 2


WLI

Rectangular waveguide line.

Format:WLI n1 n2 Width= [Height=] Length= [Name=]

Parameters:Width = Width of line (A)Height = Height of line (B) (optional, may be specified in SUB)Length= Length of lineName = Component name (optional)

Example:WLI 1 2 A=100 B=50 L=800

Range:TE10 mode assumed

The dimensional units are established by a SUB call priorto WLI. The model is based on Marcuvitz [35]. The char-acteristic impedance is the wave impedance of the TE10mode and is dispersive. The electrical length is also fre-quency dependent.

The transmission amplitude is also modeled below cutoff.Model is based on R.E. Collin, Field Theory of GuidedWaves, pp 185-195 to provide correst loss calculation nearand at cut-off. This model is useful for the design ofevanescent mode filters.

Touchstone Translation:RWG n1 n2 A= B= L= ER= RHO=


1 2


XTL

Piezoelectric resonator.

Format:XTL n1 n2 Rs= Lm= CM= CO= [Name=]

Parameters:Rs = Series resistance (ohms)Lm = Motional inductance (nanohenries)Cm = Motional Capacitance (picofarads)Co = Parallel Capacitance (picofarads)Name = Component name (optional)

Example:XTL 1 2 Rs=26 Lm=4.97e6 Cm=.012741 Co=4.18

The electrical model is given below.

Touchstone Translation:SRLC n1 n2 R=Rs L=Lm C=CmCAP n1 n2 C=Co

Default SPICE Translation:.SUBCKT X$NAME 1 2

R_series 1 3 RsL_motion 3 4 Lm nHC_motion 4 2 Cm pFC_parall 1 2 Co pF

.ENDS X$NAME

1 2

Rs ohm Lm nH Cm pFCo pF

1 2


Chapter 13

Printing and Plotting

A ll Eagleware programs are capable of producing highquality output. This output can be sent to most typesof printers and plotters, including color printers and

plotters. Graphic file formats are also supported for usewith desktop publishing programs. Regardless of thedevice you are printing to (printer or file), printed outputcan be sorted into three categories: screen dumps, high-resolution printing, and text output.

Screen dumps are exact copies of the entire view screen orof the active window. An entire screen dump is availablethrough the File menu of all Eagleware programs under“Print Screen” menu item. The “Print Window” menu itemis the same as Print Screen except that it only prints thecurrenly active window. Both functions can be accessedusing Alt-F7 and Alt-F8 function keys, respectively.

High Resolution Output is available from =SuperStar=,=SCHEMAX=, =LAYOUT=, and =M/FILTER=. High-Resolution output gives you the best quality availablefrom your printer, but is only available in certain places:most =SuperStar= windows, =SCHEMAX= plots, and=M/FILTER= layouts. It does not give you an exact dupli-cate of the screen like the screen dump option; rather, itrecalculates the screen at the full printer resolution. Theresulting print is a much higher quality display than theon-screen resolution. This is because the maximumscreen display resolutions available are not as fine as a

typical printer. PC Monitor resolutions range from640x480 up to 1600x1200, whereas a 300dpi laser printerhas a resolution of 3000x2250 (600dpi lasers have a reso-lution of 6000x4500 on letter sized paper).

Text output is available for the text portion of schematic(SCH) files from the text editor in =SCHEMAX=, forcircuit (CKT) files from the =SuperStar= text editor, for=SuperStar= simulation results from the Utility menu,and for any DSP or error window in =SuperStar= byselecting “Plot Window” from the file menu. (Since the textin a DSP or error window is not a graphic plot, =Super-Star= simply prints the text from the window in a textformat.)

PRINTING IN WINDOWS

Before printing in Windows, your system must be config-ured with a Windows printer driver; this task is usuallyperformed when Windows is first installed. If you getfurther along in the printing process and discover that adriver you need has not been loaded then you should runthe Windows 3.1 Control Panel and select the Printers iconto add new printers, select Start|Settings|Printers|AddPrinter in Windows 95, or run the Windows NT PrintManager. For more details on Windows printer drivers,the Control Panel, and Print Manager, see your Windowsmanual.

Once a printer driver has been loaded, you may easilyswitch between different modes and setups. When yourequest a printout, simply press the setup button on theprinter selection dialog box to choose the printer and toselect any options for the printer. Any changes you makewill be remembered as long as you remain within the sameEagleware program. Whenever you exit or shell from aprogram, the settings return to the default. To perma-

294 Printing and Plotting

nently change settings use the Windows Control Panel orthe Windows NT Print Manager.

The output is printed as seen, so if you have a blackbackground on screen in =SuperStar=, you will get a solidblack background on the printer. If you want a whitebackground for your =SuperStar= screen dumps, youshould select “Toggle Background Color” from the Utilitiesmenu.

Windows screen dumps can also be sent to Windows Bit-map (BMP) files by answering no to the “Send toPrinter...?” message box that comes up immediately afterselecting Print Screen or Print Window. Give the filenameyou wish to create, including the .BMP extension. Cur-rently, the BMP format is the only desktop publishingformat supported in Windows.

COMMON PRINTING QUESTIONS

What is the difference between Print Screen , PrintWindow, and Plot (High-Resolution output)?

Print Screen prints the exact contents of the screen, pixelfor pixel. This means that the quality of the print will beno better than the quality of the screen display. Plots, onthe other hand, are created to take advantage of the fullprinter resolution. Note: “Plots” are available on all kindsof printers, not just plotters. Plots generally give a higherquality printout. However, you should use screen dumpsfrom synthesis programs that do not plot or whenever youwant an exact copy of the screen. Screen Dumps can alsobe used in =SuperStar= when plots are unavailable, suchas during optimization or sensitivity analysis.

Print Window is similar to Print Screen except that it onlyprints the active window. This can be especially useful inthe synthesis programs to keep from getting an unwantedprinting outside the main window.

Printing and Plotting 295

In Windows, how do I switch my printer to land-scape mode so that plots appear “sideways” on thepage?

From the print dialog box, click on the Setup button. Asub-window will appear with a landscape option that youcan select. If you want to permanently change yourprinter to landscape mode, you can do it from within theControl Panel in Windows 3.1 or from within the PrintManager in Windows NT.

Why doesn’t the Print Screen key print a copy of thescreen?

The print screen key is controlled by Windows, not byEagleware software. Use the Alt-F7 key to print thescreen within Eagleware Software. Under Windows, thePrint Screen key never prints the screen without specialthird-party software.

When I do a screen dump from =SuperStar=, whydoes it print white on a solid black background?

=SuperStar= will print screen dumps in a WYSIWYG(what-you-see-is-what-you-get) mode. This means that ifyou are viewing plots on a black background they will alsoprint with a black background. The solution is to select“Toggle Background Color” from the Utilities menu thattoggles between black and white background colors.NOTE: This only applies for screen dumps. High-Resolu-tion plots always print with a white background.

How do I include tuned variable values with my=SuperStar= printout?

Do a Print Screen, not Print Window or Plot.

Why does my Monte Carlo analysis disappear whenI go to print it?


Monte Carlo runs contain a huge amount of data and arenot permanently stored in memory. Anytime anythingoverwrites a window containing a Monte Carlo analysis,the Monte Carlo will be erased. This even applies to theFile menu overwriting a window, so when the Print Screenoption is selected from the File menu, the Monte Carloanalysis is erased. The solution is to use the print screenor print window hot keys, Alt-F7 or Alt-F8.

NOTE: Monte Carlo analyses can only be printed inscreen dumps, not plots.

How do I make my larger schematics fit on the page?

Select Page Settings from the File menu in =SCHEMAX=.Change the “Standard Part Length” setting. This value isthe length of most parts (such as capacitors and transmis-sion lines) with one inch (25.4 mm) being the default.

How do I print all the details of my =SCHEMAX=file?

In addition to a schematic plot, you may want to simplyprint the contents of the corresponding circuit (CKT) file.This can be done with the aid of the SCH2CKT utility. SeeAppendix D for details.

In =M/FILTER= or =LAYOUT=, I’m doing layoutplots to laser printer transparencies for quick pro-totypes. How do I ensure that the dimensions areas accurate as possible?

Most laser printers will “bleed” on the edges of filled areas.This can cause severe accuracy problems for microwavefilters. You can instruct =M/FILTER= to correct for thisproblem by using the etch factor setting. Setting it to anegative value can cancel out the effect. The negative etchfactor causes all dimensions to be smaller by the specified

Printing and Plotting 297

amount. (The etch factor calculations are actually quite abit more involved than just making dimensions smaller;See the synthesis manual for details.) A typical negativeetch factor as measured on a HP LaserJet 4 is about -3mils (-0.076 mm). If a scale factor is used, the etch factormust be scaled by the inverse of the scale factor, since theetch factor is really intended for use on the final circuitboard, not as a film generation effect. Thus, if you areusing a scale factor of 2:1, the etch factor for the LaserJet4 would be entered as -1.5 mils. Also, if you need a realetch factor for your fabrication process, it should be addedto the negative etch factor. For example, if your processrequires a 1 mil etch factor and you want to print at a scaleof 2:1, then the etch factor for the LaserJet 4 would be -0.5mils. For printers other than the HP LaserJet 4 youshould measure the line widths to determine an appropri-ate etch factor.

Also, Most laser printers are less accurate in one dimen-sion. Printers are often less accurate along the verticalaxis since the paper flow is not always perfect. You shouldorient circuits so that their longest features run in themore accurate direction, generally across the page.

Remember that your laser printer cannot be any moreaccurate than its resolution, generally 300 or 600 dpi, foran accuracy of +/- 1.66 mils (0.042 mm) or +/- 0.83 mils(0.021 mm), respectively.

I want to include graphs and schematics in a desk-top publishing file. How do I do it?

You can redirect a screen dump to a Windows Bitmap(BMP) file. Simply select “Print Screen” (Alt-F7) or “PrintWindow” (Alt-F8) from any Eagleware program. A mes-sage box will ask you if you wish to send the output to aprinter; choose no, which sends the output to a BMP file.Enter the BMP filename to complete the process.


Chapter 14

Text Circuit Block

SuperStar= text files can be used instead of schematicfiles. These files are entered into the =SuperStar=text editor and are generally saved with a .CKT exten-

sion. This chapter describes the CIRCUIT block portionof a CKT file. The rest of a CKT file is identical to the textportion of a =SCHEMAX= file; see Chapter 4 for details.

CIRCUIT BLOCK

All circuit files must begin with a CIRCUIT block. Thisblock describes the networks to be analyzed. This block issometimes called a “netlist.” Writing =SuperStar= circuitfiles is better understood by considering a few simplerules.

• There should be no floating nodes.

• 0 is always datum node (ground).

• The DEF2P code connects all the elements between thespecified input and output nodes.

The example =SuperStar= circuit file, SS4T32.CKT, is oneof many example circuit files included with =SuperStar=.The schematic of this network is shown in Figure 14-1,and the circuit file is given in Table 14-1. We will nowexamine this circuit in detail. The first line is:

CIRCUIT

This indicates that the circuit description section of thecircuit file is to follow.

CAP 1 0 C=47 Q=1000 NAME=C1

This line describes a capacitor (CAP) connected betweennodes 1 and 0 (0 being ground). Figure 14-1 shows apicture of these connections. The capacitor has a value of47pF (C=47) and a Q of 1000 (Q=1000). (Q is optional anddefaults to 1 million if not specified.) This component isnamed C1 (NAME=C1). Names are optional but they canbe useful when making multiple components with identi-

1

0

2

0

3

C1

47 pF

C3

47 pF

L1

1340 nH

C2

2 pF

Figure 14-1 Schematic of the circuit shown in Table 14-1

CIRCUITCAP 1 0 C=47 Q=1000 NAME=C1SLC 1 2 L=1340 C=2 QL=120 QC=1000C1 2 0DEF2P 1 2 RESONATEWINDOWRESONATE(50)GPH S21 -30 0GPH DLY 0 200FREQSWP 95 105 101WINDOWRESONATE(50,95)GPH S21 -30 0GPH DLY 0 200FREQSWP 95 105 101

Table 14-1 SS4T32.CKT.

300 Text Circuit Block

cal paramenters as was done later in this file.

SLC 1 2 L=1340 C=2 QL=120 QC=1000

This line specifies a Series L-C network (SLC) connectedbetween nodes 1 and 2. Since this network defines boththe inductor and the capacitor, node 3 shown in Figure14-1 is not needed. The inductor is 1340nH (L=1340) witha Q of 120 (QL=120) and the capacitor is 2pF (C=2) witha Q of 1000 (QC=1000). This component is not namedsince it will not be reused later.

C1 2 0

This line reuses (makes a duplicate of) capacitor C1. Thiscould have been another CAP, but creating identical partshas two advantages. First, editing the circuit file tochange the first occurrence of a component automaticallychanges the duplicate parts. Second, circuit analysis isfaster.

DEF2P 1 2 RESONATE

This line finishes the description of the resonator network.It reduces the components described above to a two-portnetwork. Node 1 is the input of the circuit and node 2 isthe output. The defined network is assigned the name“RESONATE”.

Each network that you define must end with a DEFnPline, where n is the number of ports on the network. If youwant to reuse (make a duplicate of) a network, you can usethe name on a line with three node numbers (input,output, and reference ground). This is similar to namedcomponents but reuses the entire network. Our exampledid not reuse the RESONATOR network.

The rest of this file contains a WINDOW block. The formatof this block is described fully in Chapter 4. The resultinggraph from this file is shown in Figure 14-2.

Text Circuit Block 301

UNITS


Resistance ohmsInductance nanohenriesCapacitance picofarads1/Resistance (G) siemens (mhos)Group Delay nanosecondsFrequency megahertzElectrical Length degrees at the specified frequencyPhysical Length mils(0.001") or mm(millimeters)

=SUPERSTAR= TEXT EDITOR

=SuperStar= circuit files are standard ASCII files. Thedata files which store transistor data are also ASCII files.The ASCII file format is very common. In fact, many wordprocessors can be used to write and edit such files. How-ever, =SuperStar= includes a convenient built-in full-

Figure 14-2 =SuperStar= screen with analysis of SS4T32.CKT.


screen editor. The =SuperStar= editor is used to create thecircuit files and to enter your own S-parameter data files.

The editor is accessed by selecting Edit CKT File from theFile menu or by pressing F8. If a file has already beenopened, pressing F8 activates the editor and loads that fileinto the editor. If no file has been opened, pressing F8displays a dialog box asking whether to create a text fileor to create a schematic file. Selecting text causes a blankeditor screen to be displayed. Selecting Schematic runsthe =SCHEMAX= program.

The following options are in the Edit menu

Cut Shift-Del in WindowsCopy Ctrl-InsPaste Shift-Ins in Windows

In Windows, cutting and pasting is identical to the proce-dure used in NOTEPAD, using shift-arrows to select ablock of text. See your windows manual for details.

A complete list of editor functions is shown below.

F1 Show help file

F2 Saves the file to disk with the current filename

F9 Leaves editor (=SuperStar= will translate)

®¬¯ Moves cursor the indicated direction

¬(Backspace) Deletes the character to the left of the cursor

Home/End Moves to the beginning/end of a line

Ctrl-End Moves to the end of the file

Ctrl-Home Moves to the beginning of the file

Ctrl-®, ¬ Scrolls through file one word at a time

Ctrl-T Deletes a word

Ctrl-Y Deletes a line

Shift-Ins Pastes from buffer

Text Circuit Block 303

Ctrl-Ins Copies to buffer

PgUp/PgDn Scrolls page up/page down

Shift-Del Deletes character cursor is on. If text ismarked, cuts text to buffer

EDITING OTHER FILES

The editor may be used to edit files other than =Super-Star= circuit files. For example, S-parameter data filesmay be edited. The creation of S-parameter data files isdiscussed in the Chapter 5, Importing Device Data.

EDITOR HELP

Use the arrow keys to scroll through the circuit file line byline. You will notice a line in the status area of the screenthat begins with “Line:” This line provides the current linenumber and reference information on the syntax require-ments of the line, depending on the code at the beginningof the line. General help is accessed by pressing F1.

LEAVING THE EDITOR

To leave the editor press F9. This does not save your file.It only saves it to the editor buffer. (You will need to pressF2 or select “Save” from the File menu in order to save thefile to disk). =SuperStar= will begin circuit file translationand display the output windows.


Chapter 15

Menu Descriptions

A t the top of the =SuperStar= screen is the menu bar.It contains the File, Edit, Tune, Optimize, Stats,Utils, Window, Export, Layout, Shell, and Help

menus.

FILE MENU

The following options are listed in the File menu.

NewOpen *.CKT (Text) fileOpen *.SCH (Schematic) fileSave Circuit F2Save Circuit AsWrite S-DataTitle BoxPage SettingsPreferencesRenumber NodesEdit CKT File F8Plot Current WindowPrint Screen Alt-F7Print Window Alt-F8Exit

New - allows you to begin writing a new file. This erasesthe current file and screen. You are asked to select thenew file type: either a text file or a schematic. Select TextFile to begin writing a circuit text (netlist) file, or select

Schematic to draw the circuit using =SCHEMAX=. Referto Chapter 3 for information about entering a schematic.

Open *.CKT (Text) File - opens a previously created textcircuit file.

Open *.SCH (Schematic) File - opens a previously createdschematic file.

Save Circuit (F2) - saves your file using the currentdirectory and name. If the file is a new file and not yetnamed, the Save Circuit As dialog box will appear.

Save Circuit As - allows you to specify the name of thecircuit file, directory and disk drive before saving the file.This is handy for renaming files.

Write S-Data - automatically writes an S-parameter datafile for the circuit just analyzed. This file can then be usedby another circuit file. In this way, common buildingblocks can be designed, stored and then used in othercircuits. The automatic S-parameter output data featureof =SuperStar= may be used to interface with other engi-neering tools, such as MathCAD or plotting programs. Formore information on the format of S-parameter data files,refer to Chapter 5, Device Data.

Title Box - displays the =SCHEMAX= Title dialog box, forcustomization of the schematic page title box.

Page Settings - displays the Page Settings dialog box forspecifying custom settings in =SCHEMAX=, such as partsize, page size and page orientation.

Preferences - allows customization of =SCHEMAX= be-havior for node numbering, mouse button assignments,part rotation angle, etc.

Renumber Nodes - renumbers the nodes in the currentschematic.

306 Menu Descriptions

Edit CKT File (F8) - displays the =SuperStar= text editoror =SCHEMAX=. The text editor and netlist format arecovered in full detail in Chapter 14.

Plot Current Window - In =SuperStar=, this plots thecurrent response (the current response is in the windowwhose title bar is highlighted). In =SCHEMAX=, thisplots the schematic. Please note that in =SCHEMAX=,only the portion of the schematic inside the page boundaryis plotted. Plots can be done to any type of printeror plotter.

Print Screen (Alt-F7) - prints the entire screen, includingany objects outside the =SuperStar= or =SCHEMAX=window boundary. If the window is maximized, this optionworks exactly like Print Window.

Print Window (Alt-F8) - prints only the =SuperStar= or=SCHEMAX= window. If the window is maximized, thisoption works exactly like Print Screen.

Exit - exits =SuperStar= and returns to Windows.

EDIT MENU

The following options are listed in the Edit menu.

Cut Shift+DeleteCopy Ctrl+InsertPaste Shift+InsertDuplicate Ctrl+DMirror F6Rotate F3Details F4All Details Shift+F4SubstratesAdd Question Marks To All Parts=SCHEMAX= User ToolbarsStart Model Editor

Menu Descriptions 307

Cut (Shift+Delete) - copies the current selection into thebuffer and deletes the selected object(s).

Copy (Ctrl+Ins) - copies the current selection into thebuffer but does not delete the selected object(s).

Paste (Shift+Ins) - pastes the buffer into the currentschematic or netlist.

Duplicate (Ctrl+D) - duplicates the currently selectedobject(s). This is equivalent to a copy and paste sequence.

Mirror (F6) - flips the current selected component aboutits horizontal or vertical axis.

Rotate (F3) - rotates the selected component by the “PartConstrain Angle” specified in the Preferences dialog.

Details (F4) - displays the part dialog for the selectedcomponent.

All Details (Shift+F4) - displays the part dialog for allcomponents sequentially, in order of placement.

Substrates - opens the Substrates dialog for editing anddefining or adding a substrate.

Add Question Marks To All Parts - forces all componentvalues to be tunable. This only adds question marks tonumerical part values. In other words, if a variable isused, it will not be made tunable.

=SCHEMAX= User Toolbars - allows customization of theUser toolbars. Buttons can be created and deleted bychoosing this option.

Start Model Editor - opens the =SCHEMAX= model editor.

TUNE MENU

The following options are listed in the Tune menu.

Goto Tune AreaReload CKT From Disk


Re-TranslateUpdate Solid Traces F5Return to Solid Traces Shift+F5Auto-TranslateAuto-Replace

Goto Tune Area - moves the input focus to the tune bar.

Reload CKT From Disk - reloads the netlist or schematicfrom the file, restoring the last saved settings.

Re-Translate - retranslates the netlist or schematic, up-dating the response and erasing any unsaved tuned oroptimized values.

Update Solid Traces (F5) - updates the current dottedtraces to solid ones.

Return to Solid Traces (Shift+F5) - restores the originaltranslation values, overwriting any tuned or optimizedvalues since the last update.

Auto-Translate - automatically translates whenever theschematic or netlist window is changed. For example, ifthe schematic window and the response window are side-by-side (tiled), the response automatically updates if theschematic is changed. If this option is not enabled, =Su-perStar= asks if you want to re-translate.

Auto-Replace - automatically replaces tuned or optimizedvalues into the netlist or schematic whenever the editor isinvoked.

OPTIMIZE MENU

The following options are listed in the Optimize menu.

AutomaticPattern SearchGradientSmooth Background OperationShow Optimization Targets


Automatic - optimizes your circuit with =SuperStar=choosing between pattern search and gradient optimiza-tion algorithms, switching as necessary.

Pattern Search - starts the pattern search optimizer.=SuperStar= prompts for the initial step size when thisoption is selected. This type of search is most effective inthe final stages of optimization.

Gradient - starts the gradient optimizer. This type ofsearch is most effective in the early stages of optimization.

Smooth Background Operation - Toggle (check-marked)option for better mouse and keyboard operation duringoptimization. Having this option selected will slow downoptimization by up to 20%, but is especially useful inWindows when multitasking.

Optimization is covered fully in Chapter 6, Optimization.

Show Optimization Targets - chooses whether to displayoptimization overlays on =SuperStar= responses. Theseoverlays appear as dashed lines on rectangular plots,Smith Charts, and polar graphs.

STATS MENU

The following options are listed in the Stats menu.

Monte CarloSensitivityYield OptimizationDesign CenteringSetup Monte Carlo

Monte Carlo - evaluates circuit behavior for a sample runsize with a random distribution of component valueswithin specified limits. You must first mark elements fortuning with a “?” in the circuit file before you can run aMonte Carlo analysis.


Sensitivity - displays the sensitivity of each componentvalue marked with a “?” in the circuit file. Sensitivityanalysis characterizes relationships between componentsand the circuit responses.

Yield Optimization - starts yield optimization using theconstraints defined in Monte Carlo setup and in the cur-rent yield block. See Chapter 6 for information about yieldoptimization.

Design Centering - attempts to improve the yield of yourcircuit. Design centering should be preceded with thor-ough optimization. Design centering should be used inconjunction with yield optimization to obtain the bestpossible yield percentage.

Setup Monte Carlo - Displays the Monte Carlo Setupdialog. This box allows specification of the randomnumber seed, random number probability distribution,and component tolerance ranges.

UTILS MENU

The following options are listed in the Utils menu.

Display MarkersSave Marker BlocksRedistribute MarkersToggle Grid StyleToggle Background Color

Display Markers - toggles the markers off and on. Whenmarkers are off, graphs are larger and tuning is faster.

Save Marker Blocks - saves the marker frequencies in thecircuit file so they are remembered in your next session.

Redistribute Markers - evenly distributes graph markersover the frequency range of each window.

Toggle Grid Style - toggles between the older crosshairstyle of grid and the new solid line style. You will probably


prefer the new style; the older style is retained for com-patibility with older versions of =SuperStar=.

Toggle Background Color - toggles the background color ofthe response windows between black and white. In Win-dows, you will probably want to use black for viewing thescreen and white for screen dumps.

WINDOW MENU

The following options are listed in the Window menu.

Tile HorizontalTile VerticalCascadeNext F6CloseClose AllMaximize/RestoreOpen All ResponsesError MessagesView Variables

Tile Horizontal - tiles allwindows horizontally.

Tile Vertical - tiles all windows vertically.

Cascade - cascades the windows,placing the current (high-lighted) window in front and stepping other windowsbehind it.

Next (F6) - highlights the next window.

Close - Removes the current window from the screen.

Close All - removes all windows from the screen.

Maximize/Restore - maximizes the highlighted window tofit the screen. Selecting this option again will restore thewindow to its previous position.

Open All Responses - opens all response windows after oneor more have been closed.


Error Messages - opens the Error dialog box which dis-plays error messages incurred during translation or anyoperation warnings. This box is displayed automaticallyif there are translation errors.

View Variables - opens a window which lists currentvalues of user-defined variables from the EQUATE block.Variables are discussed in Chapter 7, Equations.

EXPORT MENU

The following options are listed in the Export Menu.

Export Touchstone FileExport SPICE FileEdit SPICE Command TextSPICE PreferencesShow SPICE Details

Export Touchstone File - creates a Touchstone file from thecurrent schematic.

Export SPICE File - creates a SPICE file from the currentschematic.

Edit SPICE Command Text - opens the SPICE text editor.This text will be appended to SPICE files when exported.Any subcircuits or post-processing commands should bedeclared here.

SPICE Preferences - allows specification of the targetSPICE version, and termination options.

Show SPICE Details - selects whether to display SPICEexport details on =SCHEMAX= part dialogs when opened.

LAYOUT MENU

The following options are shown in the Layout menu.

Edit LayoutFootprint Editor


Edit Layout - opens the layout editor and displays thecurrent layout. If a layout has not yet been created for thecurrent schematic, the Layout Preferences dialog is dis-played.

Footprint Editor - opens the layout Footprint Editor forcreating or editing footprints.

SHELL MENU

The following options are displayed in the Shell menu.

Run =A/FILTER=Run =EQUALIZE=Run =FILTER=Run =MATCH=Run =M/FILTER=Run =OSCILLATOR=Run =TLINE=

These options shell to other Eagleware programs. Aftercreating a circuit or schematic file, you may return to=SuperStar= or continue the active program. If you re-turn, =SuperStar= automatically loads the circuit file justcreated and displays the response(s).

HELP MENU

The following options are shown in the Help menu.

ContentsSearch For Help On...About =SuperStar=

Contents - displays the help file contents.

Search For Help On - opens the search dialog for searchingthrough the available help topics.

About =SuperStar= - displays the software version, freememory available, and Eagleware copyright information.


Appendix A

S-Parameters

T he purpose of this chapter is to summarize networkanalysis concepts and to define some of the parame-ters plotted by =SuperStar=.

Networks are considered as “black boxes”. Because thenetworks are assumed to be linear and time invariant, thecharacteristics of the networks are uniquely defined by aset of linear equations relating port voltages and currents.A number of network parameter types have been devel-oped for this purpose, including H, Y, Z, S, ABCD, andothers. These parameters may be used to compute anddisplay network responses and to compute quantities use-ful for circuit design such as Gmax (maximum gain) andgain circles. Each parameter type has advantages anddisadvantages. Carson [1] and Altman [2] provide addi-tional information.

S-PARAMETERS

S-parameters have earned a prominent position in RFcircuit design, analysis, and measurement. Parametersused earlier in RF design, such as Y-parameters, requireopens or shorts on ports during measurement. This is anearly impossible constraint for high-frequency broad-band measurements. Scattering parameters [3, 4] (S-pa-rameters) are defined and measured with the portsterminated in a characteristic reference impedance. Mod-ern network analyzers are well suited for measuring S-pa-

rameters. Because the networks being analyzed are oftenemployed by insertion in a transmission medium with acommon characteristic reference impedance, S-parame-ters have the additional advantage that they relate di-rectly to commonly specified performance parameterssuch as insertion gain and return loss.

Two-port S-parameters are defined by considering a set ofvoltage traveling waves (see Figure A-1). When a voltagewave from a source is incident on a network, a portion ofthe voltage wave is transmitted through the network, anda portion is reflected back toward the source. Incident andreflected voltages waves may also be present at the outputof the network. New variables are defined by dividing thevoltage waves by the square root of the reference imped-ance. The square of the magnitude of these new variablesmay be viewed as traveling power waves.

|a1|2 = incident power wave at the network input

|b1|2 = reflected power wave at the network input

|a2|2 = incident power wave at the network output

|b2|2 = reflected power wave at the network output

Figure A-1 Two-port network depicting incident and reflectedvoltage waves.

316 S-Parameters

These new variables and the network S-parameters arerelated by the expressions

Terminating the network with a load equal to the refer-ence impedance forces a2 = 0. Under these conditions

S11 is then the network input reflection coefficient and S21is the gain or loss of the network.

Terminating the network at the input with a load equal tothe reference impedance and driving the network from theoutput port forces a1 = 0. Under these conditions

b a S a S1 1 11 2 12= +

b a S a S2 1 21 2 22= +

Sba

a111

12 0= =,

Sba

a121

21 0= =,

Sba

a212

12 0= =,

Sba

a222

21 0= =,

Sba11

1

1

=

Sba21

2

1

=

Sba22

2

2

=

S-Parameters 317

S22 is then the network output reflection coefficient andS12 is the reverse gain or loss of the network.

Linear S-parameters are unitless. Since they are basedon voltage waves, they are converted to decibel format bymultiplying the log of the linear ratio by 20. It is notalways obvious whether an author is refering to linear ordecibel parameters. To avoid this confusion, the bookOscillator Design and Computer Simulation and Versions5.4 and earlier of =SuperStar= use C for linear S-parame-ters and S for the decibel form. This is somewhat uncon-ventional. Version 6.0 and later of =SuperStar= alsosupports the convention MAG[S21] which is linear anddB[S21] which is the decibel form. With reflection pa-rameters, the linear form is often refered to as a relectioncoefficient and the decibel form as return loss.

S11(dB)=input reflection gain=20log S11

S22 (dB)=output reflection gain=20log S22

S21(dB)=forward gain=20log S21

S12(dB)=reverse gain=20log S12

S21 and S12 are the forward and return gain (or loss) whenthe network is terminated with the reference impedance.The gain when matching networks are inserted at theinput, output, or both is described later.

S11 and S22 coefficients are less than 1 for passive net-works with positive resistance. Therefore, the input andoutput reflection gains, S11 and S22, are negative decibelnumbers. Throughout Eagleware material, the decibelforms S11 and S22 are referred to as return losses, inagreement with standard industry convention. To bemathematically correct, they have been left as negative

Sba12

1

2=

318 S-Parameters

numbers. As such, the rigorous convention would be tocall them return gain.

Input VSWR and S11 are related by

The output VSWR is related to S22 by an analogousequation. A circle of constant radius centered on theSmith chart is a circle of constant VSWR. The complexinput impedance is related to the input reflection coeffi-cients by the expression

The output impedance is similarly related to S22.

SAMPLE S-PARAMETER DATA

Given below is S-parameter data for an HP/AvantekAT10135 GaAsFET transistor biased at 2 volts and 25milliamps. The data was obtained from the manufacturerand is typical of data for over 3000 devices which isincluded with=SuperStar=.

The first line, # MHz S MA R 50, specifies that the unitsof the frequency in the first column is megahertz, the datais S-parameter data with the magnitude in linear formatand the measurement reference impedance is 50 ohms.Lines which begin with ! are comment lines.

S-parameter data for this device is given from 500 to12000 MHz. =SuperStar= interpolates this data to deter-mine the S-parameters at intermediate frequencies.When a sweep is requested which is outside the frequencyrange of available data, =SuperStar= displays a warningand extrapolates the data. Extrapolation of S-parameterdata is not recommended. It is better to manually add

VSWRS

S=

+−

1

111

11

Z ZS

Sinput o= +−

1

111

11

S-Parameters 319

frequency points using your knowledge of transistor be-havior at extreme frequencies.

The second portion of the file contains noise data for thedevice. =SuperStar= assumes noise data begins when thefrequency in the first column stops increasing. Althoughnot robust, this is a standard convention.

Additional information on data files is given in the chap-ter, Device Data.

# MHz S MA R 50! ATF-10135 S AND NOISE PARAMETERS! Vds=2V Id=25mA! LAST UPDATED 11-09-88

!FREQ S11 S21 S12 S22!MHZ MAG ANG MAG ANG MAG ANG MAG ANG

500 .98 -18 5.32 163 .020 78 .35 -91000 .93 -33 5.19 147 .038 67 .36 -192000 .79 -66 4.64 113 074 59 .30 -313000 .64 -94 4.07 87 .110 44 .27 -424000 .54 -120 3.60 61 .137 31 .22 -495000 .47 -155 3.20 37 .167 13 .16 -546000 .45 162 2.88 13 .193 -2 .08 -177000 .50 120 2.51 -10 .203 -19 .16 458000 .60 87 2.09 -32 .210 -36 .32 489000 .68 61 1.75 -51 .209 -46 .44 3810000 .73 42 1.52 -66 .207 -58 .51 3411000 .77 26 1.26 -82 .205 -73 .54 2712000 .80 14 1.12 -97 .200 -82 .54 15

!FREQ Fopt GAMMA OPT RN/Zo!MHZ dB MAG ANG

500 0.4 .93 12 0.851000 0.4 .85 24 0.702000 0.4 .70 47 0.464000 0.5 .39 126 0.366000 0.8 .36 -170 0.128000 1.1 .45 -100 0.3812000 1.4 .60 -41 1.10

Figure A-2 is a graphic display of the AT10135 S-parame-ter plotted by =SuperStar= using the schematic fileSPARAM.SCH.

320 S-Parameters

STABILITY

Because S12 of devices is not zero, a signal path exists fromthe output to the input. This feedback path creates anopportunity for oscillation. The stability factor, K, is

where

D = S11S22 - S12S21

From a practical standpoint when K>1, S11<1, and S22<1,the two-port is unconditionally stable. These are oftenstated as sufficient to insure stability. Theoretically, K>1is insufficient to insure stability, and an additional condi-tion should be satisfied. One such parameter is B1 whichshould be greater than zero.

KS S D

S S=

− − +1

211

2

22

2 2

12 21

Figure A-2 =SuperStar= plot of the Avantek AT10135 GaAsFETtransistor S-parameter data.

S-Parameters 321

Stability circles may be used for a more detailed analysis.The load impedances of a network which ensure thatS11<1 are identified by a circle of radius r centered at Con a Smith chart. The output plane stability circle is

This circle is the locus of loads for which S11 = 1.The regioninside or outside the circle may be the stable region.

The input plane stability circle equations are the same asthe output plane equations, with 1 and 2 in the subscriptsinterchanged.

B S S D1 1 011

2

22

2 2= + − − >

CS D

S Dout

22 11

22

2 2

−

−

S * *c hr

S S

S Dout =

−12 21

22

2 2

Figure A-3 Input and output plane stability circles for the AT10135GaAsFET transistor.

322 S-Parameters

Shown in Figure A-3 are the input plane stability circleson the left and the output plane stability circles on theright for the Avantek AT10135 GaAsFET. The shadedregions are potentially unstable. At the input, the stabil-ity circle with marker 1 indicates sources with a smallresistive component and inductive reactance of about 200ohms are unstable. Circles 2 and 3 are also unstable withlow resistance and certain inductive source impedances.At the output plane on the right, at 500 MHz, a wide rangeof inductive loads is potentially unstable.

When designing an amplifier the first step is to examinethe stability circles of the device without the matchingcircuit present. The grounding which will be present atthe emitter or source should be included in the analysis.This stability data is used to 1) add stabilizing componentssuch as shunt input and output resistors for bipolars orinductance in the source path for GaAsFETs and to 2)select an input and output matching network topologywhich properly terminates the device (at low and highfrequencies) for stability.

In the example above, matching networks with a smallseries capacitor adjacent to the device would insure ca-pacitive loads at low frequencies, thus enhancing stability.This is probably sufficient for the input. However, consid-ering that device S-parameter data is approximate andsince the output plane of this device is more threatening,it would be prudent to stabilize this device in addition tousing series capacitors.

STABILITY SHOULD BE CHECKED NOT ONLY ATTHE AMPLIFIER OPERATING FREQUENCIES BUTALSO OVER THE ENTIRE FREQUENCY RANGE FORWHICH S-PARAMETER DATA IS AVAILABLE.

S-Parameters 323

MATCHING

One definition of network gain is the transducer powergain, Gt. Transducer power gain is the power delivered tothe load divided by the power available from the source.

Other gain definitions include the power gain, Gp, and theavailable power gain, Ga.

The S-parameter data for the network is measured witha source and load equal to the reference impedance. If thenetwork is not terminated in the reference impedance, Gtcan be computed from the reflection coefficients of theterminations on the network and the S-parameters of thenetwork. At this point we have multiple sets of reflectioncoefficients: those of the terminations and S11 and S22 ofthe network. To avoid confusion the termination reflec-tion coefficients are given a different symbol, Γ.

The transducer power gain with the network inserted ina system with arbitrary source and load reflection coeffi-cients is [4].

where

ΓS= reflection coefficient of the source

GP

Ptdelivered to load

available from source

= ~ ~

~ ~

GP

Ppdelivered to load

input to network

= ~ ~

~ ~

GP

Paavailable from network

available from source

= ~ ~

~ ~

GS

S S S St

S L

S L L S

=− −

− − −

21

2 2 2

11 22 21 12

2

1 1

1 1

Γ Γ

Γ Γ Γ Γ

e je jb gb g

324 S-Parameters

ΓL= reflection coefficient of the load

If and are both zero, then

Gt=S21

or

Gt(dB)=20log S21=S21(dB)

Therefore, when a network is installed in a system withsource and loads equal to the reference impedance, S21 isthe network transducer power gain in decibels.

Because S11 and S22 of a network are not in general zero,a portion of the available source power is reflected fromthe network input and is dissipated in the source. Theinsertion of a lossless matching network at the input(and/or output) of the network could increase the gain ofthe overall system if reflections toward the source werereduced. Shown in Figure A-4 is a two-port network withlossless matching networks inserted between the networkand the source and load.

GMAX AND MSG

When the input and output networks are simultaneouslydesigned for maximum gain, there is no reflection at thesource or load. The maximum transducer power gain,Gmax, is given by

ΓS ΓL

Figure A-4 Two-port with input and output matching networksadded. C depicts the linear form of the two-port S-parameters.

S-Parameters 325

The maximum stable gain, MSG, is defined as Gmax withK=1. Therefore

A =SuperStar= plot of GMAX returns Gmax when K>1 andMSG when K<1.

Again, acheiving this maximum gain requires that theinput network is designed such that ΓS is the complexconjugate of S11 and ΓL is the complex conjugate of S22.=SuperStar=returns the required reflection coefficients,impedance and admittance for the input and output net-works as GM1, GM2, ZM1, ZM2, YM1 and YM2, respec-tively.

THE UNILATERAL CASE

Historically, to simplify the complex equation for Gt for thenetwork in Figure A-4, S12 was set to zero. At higherfrequencies, where the device S12 is typically larger, thisassumption is less valid. The assumption simplifies man-ual and graphical design but is unnecessary in moderncomputer-assisted design. The assumption also allowsfactoring the above equation into terms that provide in-sight into the design process. If S12 =0, then

where

Gtu=unilateral transducer power gain

GS

SK Kmax = − −21

12

2 1e j

MSGS

S= 21

12

GC

CC

tuS

S

L

L

=−

−−

−1

1

1

1

2

11

2 21

22

22

2

ΓΓ

ΓΓ

326 S-Parameters

When both ports of the network are conjugately matched,and S12 = 0,

The first and third terms indicate the gain increaseachievable by matching the input and output, respectively.If S11 or S22 approach 1, substantial gain improvement isachieved by matching. Matching not only increases thenetwork gain, but reduces reflections from the network.

When network gain flatness across a frequency band ismore desirable than minimum reflections, the losslessmatching networks are designed to provide a better matchat frequencies where the two-port gain is lower. By carefuldesign of amplifier matching networks, it is possible toachieve a gain response flat within fractions of a decibelover a bandwidth of an octave or more.

GAIN CIRCLES

When the device is complex conjugately matched, thetransducer gain is Gmax and if the device is terminatedwith the same resistance used to measure the deviceS-parameters the transducer gain is S21. The gain witharbitrary terminations can be visualized on the Smithchart using gain circles.

=SuperStar= plots three forms of gain circles: transducergain unilateral circles, GU1 for the input network andGU2 for the output network, power gain output networkcircles, GP, and available gain input network circles, GA.

Shown in Figure A-5 are the input and output unilateraltransducer gain circles, GU1 and GU2, of the AvantekAT10135 GaAsFET transistor. =SuperStar= circles areplotted at the frequency of the first marker, in this case2500 MHz. Marker 1 is plotted at the center of thesmallest circle, the point of maximum gain. The gain at

GS

SS

u max =− −

1

1

1

111

2 21

2

22

2

S-Parameters 327

the circumference of each circle of increasing radius is 1dB lower than the previous inside circle.

The arc which is orthogonal to the gain circles is the locusof smallest circle center points from the lowest to highestsweep frequency. Tuning the first marker frequencymoves the center of the circles along this arc.

Notice that a complex conjugate match at the input im-proves the gain by over 3 dB in relation to an unmatched50 ohm source impedance. However, matching the outputprovides less than 1 dB gain improvement. An examina-tion of the device S-parameter data at 2500 MHz revealsthat the output is originally closer matched to 50 ohmsand it is not surprising that a matching network would beless beneficial.

NOISE CIRCLES

To acheive the best available noise figure from a device thecorrect impedance must be presented to the device. Theimpedance resulting in the best noise performance is in

Figure A-5 Input and output transducer unilateral gain circles at2500 MHz for the AT10135 GaAsFET transistor.

328 S-Parameters

general neither equal to 50ohms or the impedancewhich results in minimumreflection at the source.

The Avantek AT10135GaAsFET transistor S-pa-rameter data given earlierincludes noise data. Thisdata is comprised of fournumbers for each fre-quency. These numbers areNFopt(dB), the optimumnoise figure when correctlyterminated, Γopt magni-tude and angle, the termi-nating impedance at thedevice input whichacheives NFopt and Rn/Zo, a sensitivity factor whicheffects the radius of the noise circles.

Noise circles plotted by =SuperStar= for the AT10135 at2500 MHz are given in Figure A-6. Circles of increasingradius plotted by =SuperStar= represent noise figure de-gredations of 0.25, 0.5, 1, 1.5, 2, 2.5, 3 and 6 dB. In thiscase, direct termination of the device with a 50 ohm sourceresults in a degredation of the noise figure of 1 dB. Thearc orthogonal to the circles is the locus of Γopt versusfrequency.

SMITH CHART

In 1939, Philip H. Smith published an article describing acircular chart useful for graphing and solving problemsassociated with transmission systems [36]. Although thecharacteristics of transmission systems are defined bysimple equations, prior to the advent of scientific calcula-tors and computers,evaluation of these equations was best

Figure A-6 Noise circles for theAT10135 GaAsFET transistor at2500 MHz.

S-Parameters 329

accomplished using graphical techniques. The Smithchart gained wide acceptance during the development ofthe microwave industry. It has been applied to the solu-tion of a wide variety of transmission system problems,many of which are described in a book by Philip Smith[37]. The Smith chart as displayed by the =SuperStar=computer program is shown in Figure A-7. Labels fornormalized real and reactive components are added.

The design of broadband transmission systems using theSmith chart involves graphic constructions on the chart

Figure A-7 Simplified unity radius impedance Smith chart asplotted by =SuperStar=.

330 S-Parameters

repeated for selected frequencies throughout the range ofinterest. Although the process was a vast improvementover the use of a slide rule, it is tedious. Modern interac-tive computer programs with high-speed tuning and opti-mization procedures are much more efficient. However,the Smith chart remains an important tool for instruc-tional use and as a display overlay for computer-generateddata. The Smith chart provides remarkable insight intotransmission system behavior.

The standard unity-radius impedance Smith chart mapsall positive resistances with any reactance from -∞ to +∞onto a circular chart. The magnitude of the linear form ofS11 or S22 is the length of a vector from the center of thechart, with 0 length being a perfect match to the referenceimpedance and 1 being total reflection at the circumfer-ence of the chart. The underlying grids of the Smith chartare circles of a given resistance and arcs of impedance.

The reflection coefficient radius of the standard Smithchart is unity. Compressed Smith charts with a radiusgreater than 1 and expanded charts with a radius lessthan 1 are available.

High impedances are located on the right portion of thechart, low impedances on the left portion, inductive reac-tance in the upper half, and capacitive reactance in thelower half. Real impedances are on a line from the left toright, and purely reactive impedances are on the circum-ference. The angle of the reflection coefficient is measuredwith respect to the real axis, with zero degrees to the rightof the center, 90o straight up, and -90o straight down.

The impedance of a load as viewed through an increasinglength of lossless transmission line, or through a fixedlength with increasing frequency, rotates in a clockwisedirection with constant radius when the line impedanceequals the reference impedance. If the line and referenceimpedances are not equal, the center of rotation is not

S-Parameters 331

about the center of the chart. One complete rotationoccurs when the electrical length of the line increases by180o. Transmission line loss causes the reflection coeffi-cient to spiral inward.

The length of a vector from the center to a given point onthe Smith chart is the magnitude of the reflection coeffi-cient. The angle of that vector with respect to the real axisto the right is the phase angle of the reflection coefficient.Several common definitions are used to represent thelength of this vector. They are referred to as radiallyscaled parameters because they relate to a radial distancefrom the center towards the outside circle of the chart.Given below is a table of radially scalled parameters.

S11 S11(dB) VSWR S21(dB)0.010 -40.0 1.020 -0.00040.032 -30.0 1.065 -0.00440.056 -25.0 1.119 -0.01360.100 -20.0 1.222 -0.04360.126 -18.0 1.288 -0.06950.158 -16.0 1.377 -0.10980.178 -15.0 1.433 -0.13980.200 -14.0 1.499 -0.17730.224 -13.0 1.577 -0.22360.251 -12.0 1.671 -0.28260.299 -10.5 1.851 -0.40670.316 -10.0 1.925 -0.45690.333 -9.54 2.000 -0.51150.355 -9.00 2.100 -0.58500.398 -8.00 2.323 -0.74900.447 -7.00 2.615 -0.9681

S11 S11(db) VSWR S21(dB)0.500 -6.02 3.000 -1.24940.562 -5.00 3.570 -1.64840.600 -4.44 3.997 -1.93820.631 -4.00 4.419 -2.20520.707 -3.01 5.829 -3.01030.714 -2.92 6.005 -3.09620.794 -2.00 8.724 -4.32310.800 -1.94 8.992 -4.43700.891 -1.00 17.39 -6.85880.900 -0.92 19.00 -7.21250.950 -0.446 39.00 -10.1100.980 -0.175 99.00 -14.0230.990 -0.087 199.0 -17.012

Table A-1 Radially scaled parameters. S21 assumes a losslessreactive network.

332 S-Parameters

Appendix B

How =SuperStar= Works

T he execution speed of SuperStar= is largely a resultof a unique network reduction engine developed byEagleware in 1992. This node elimination algorithm

offers the flexibility and ease-of-use of nodal analysiswhile providing the numeric efficiency and executionspeed of two-port analysis techniques. It is significantlyfaster than the sparse matrix technique which is used inother simulators. =SuperStar= also incorporates otherspeed enhancing techniques such as element classes andoutput parameter classes. These techniques and carefulcode profiling make =SuperStar= the fastest simulatoravailable today, providing far more interactive and effec-tive tuning, optimization, 3D mapping and yield optimi-zation. These techniques are described later in thischapter, but first let’s review conventional nodal andtwo-port techniques.

When a network is linear and time invariant, it is uniquelydefined by a set of simple equations with coefficientsrelating port voltages and currents. A number of networkparameter types have been developed for this purpose,including H, Y, Z, S, ABCD, and others. Certain parametersets have advantages and disadvantages for a given ap-plication. Carson [1] and Altman [2] include additionalnetwork parameter review and other analysis considera-tions.

S-PARAMETERS

S-parameters have earned a prominent position in RFcircuit design, analysis, and measurement. Parametersused earlier in RF design, such as Y-parameters, requireopens or shorts on ports during measurement. This is adifficult constraint for high-frequency broadband meas-urements. Scattering parameters [3, 4] (S-parameters)are defined and measured with the ports terminated in afinite characteristic impedance. Modern network analyz-ers are designed to measure S-parameters. In the finalapplication, networks are often employed by insertion ina transmission medium with a finite characteristic imped-ance, therefore S-parameters have the additional advan-tage that they relate directly to commonly specifiedperformance parameters such as insertion gain and re-turn loss. Appendix A contains a brief review of S-parame-ter theory.

TWO-PORT INTERCONNECTIONS

S-parameters are convenient parameters for display andinterface with measurement equipment. However, otherparameters are more numerically efficient for the compu-tation of the network response. For example, ABCD pa-rameters are useful for computing the response ofcascaded two-ports since the ABCD parameters of thetwo-ports are simply multiplied.

It is efficient to create and maintain two-ports as ABCDparameters because cascading is generally the most oftenused two-port connection. When output data is required,the ABCD parameters of the overall network are con-verted to the desired parameter type and are denormal-ized to the specified termination resistances.

To connect two-ports in parallel, the Y-parameters of thetwo-ports are added. The ABCD parameters of each two-port are converted to Y-parameters, the Y-parameters are

334 How =SuperStar= Works

added, and the resulting Y- parameters are converted backto ABCD parameters. The series connection of two-portsis accomplished in a similar way using Z-parameters.

Certain network topologies cannot be analyzed by con-nected two-port methods. These networks could be ana-lyzed by applying the foregoing principles to N-portnetworks. However, more frequently the network is de-scribed nodally, and the indefinite Y or other matrix for-mulation is used [1]. The indefinite Y matrices of thecomponent networks are added, thus creating an NxNmatrix, where N is the number of nodes, not including thedatum node. This indefinite Y matrix is then reduced toa 2x2 matrix to compute output data.

COMPUTER EXECUTION TIME

The response of networks is computed with greater nu-meric efficiency using two-port techniques than withnodal techniques. For two-port analysis the number ofrequired calculations grows linearly with circuit complex-ity while for nodal analysis the number of required calcu-lations grows roughly with the 3rd power of the numberof nodes. Figure B-1 shows the execution times for a setof bandpass filters with 4 to 12 nodes. Nodal and two-portanalysis techniques were compared using a 33 MHz 80486computer. The time required to compute and display theresponse for 21 frequency points is included. With sparsematrix techniques, the number of caluclations growsroughly as the 2nd power of the number of nodes, fasterthan conventional matrix reduction techniques, but sig-nificantly slower than two-port analysis.

Why do we have such a strong interest in execution speed?Our first experience with circuit simulation involvedbatch mode processing, and later, time sharing. Althoughthese were helpful, the absence of the interactivity andquickness associated with bench tuning was frustrating.

How =SuperStar= Works 335

When we began the design of a simulator, speed andinteractivity were high on the priority list. Once real-timetuning and fast optimization are experienced, their advan-tages become obvious. Conventional nodal analysis is soinefficient that even fast hardware doesn’t provide real-time analysis, particularly with larger networks.

NODE ELIMINATION ALGORITHM

The =SuperStar= node elimination algorithm is based onmodern graph theory. It is relatively complex but is exe-cuted only once during circuit translation. The resultinginternal code is as numerically efficient as manually cre-ated two-port description files.

If a pure two-port description is not feasible, the algorithmgenerates a hybrid nodal/two-port list. As Figure B-1reveals, the slowness of a nodal analysis is a function of

Figure B-1 Execution times for bandpass filters of increasingorder for two-port and nodal analysis models.


the number of nodes. Even when a pure two-port descrip-tion is unavailable, the algorithm can reduce the numberof nodes and create a more numerically efficient descrip-tion. It is rare that the number of nodes isn’t significantlyreduced.

COMPUTATIONAL CLASSES

=SuperStar= incorporates two other important speed en-hancing techniques; element and output classes.

While cascading networks using ABCD parameters ismore efficient than nodal circuit reduction, certain net-work classes can be reduced with even fewer calculationsthan ABCD techniques. For example, the impedances ofcascaded series branches simply are added. Other effi-cient special cases exist. Since these techniques don’twork for the general case, =SuperStar= automaticallymaintains a record of element classes and applies thesimplest reduction method available for each class.

Output data is also classified. Certain data such as noisefigure and group delay require calculations unnecessaryfor scalar data such as gain and return loss. This isanalogous to the differences in complexity and cost ofscalar and vector network analyzers. =SuperStar= auto-matically applies the most elegant solution available.

CODE PROFILING

Throughout its development history, =SuperStar= hasbeen subjected to careful code profiling. Bottleneckswhich reduce execution speed are not always intuitive.For example, the simple process of initializing a matrixwith zeros is slow. Once discovered, such bottlenecks areoften more efficiently coded.


OTHER SPEED ENHANCEMENTS

Other speed enhancing techniques in =SuperStar= in-clude:

• Certain critical algorithms are written in assembly.

• Graphic routines, which are typically slow, are carefullyselected and designed.

• EQUATION block equations are reduced to sequentialoperations for run-time use.

• The program was developed with a consistent philosophyemphasizing execution speed.

CIRCUIT SIMULATOR TYPES

We often receive questions on how =SuperStar= comparesto other circuit simulators. Popular modern circuit simu-lators fall into three major categories: linear simulators,SPICE-derived programs, and harmonic balance tech-niques. Linear simulators, such as =SuperStar=, utilizeclosed form equations to compute the frequency domainresponse of linear circuits. SPICE products are almostinvariably based on SPICE2 or SPICE3, developed at theUniversity of California, Berkeley. SPICE products solvenon-linear differential equations for a network using it-erative techniques. Faster closed-form solutions are un-known. Both the frequency and time domains aresupported.

Harmonic balance provides non-linear analysis, but isrestricted to steady state behavior. Models based onSPICE are often used.

Each simulator category compromises some desirable at-tribute. The most demanding design requirements arebest satisfied using more than one simulator class. Someof the advantages and disadvantages of these three classesare:


LINEAR SIMULATORSAdvantages: Highly accurate

Device modeling is straightforwardFast and interactiveTuning and optimization

Disadvantages: Frequency domain onlyLinear only

SPICE SIMULATORSAdvantages: Frequency, time, and transient domains

DC (bias) simulationLinear and non-linear

Disadvantages: Painfully slowDevice models are elusiveAccuracy is compromisedCertain problems may not converge

HARMONIC BALANCEAdvantages: Linear and non-linear

Faster than SPICE for many circuits

Disadvantages: Steady-state onlyDevice models are elusiveMuch slower than linear simulation

The disadvantages of SPICE simulation worsen with in-creasing frequency. Also, time domain data is often of lessinterest to higher frequency engineers because of thedifficulty associated with measuring voltages at high fre-quencies. Accurate high frequency measurement equip-ment operates in the frequency domain. At lowerfrequencies, voltage data is less elusive and more insight-ful. For these reasons, low frequency (below about 1 MHz)engineers typically use SPICE simulators and high fre-quency engineers use linear simulators. Today, we areseeing more and more cross utilization of these simulatorclasses. This is healthy. High frequency engineers, whenthe extra effort of model study and accuracy checking arejustified, can benefit from time domain and non-linear


simulation. Low frequency engineers can benefit from thereal-time tuning and optimization capabilities of a linearsimulator to optimize the frequency domain performanceof the circuit.

Harmonic balance simulators grew out of a need to resolvedifficulties associated with SPICE simulation; slow execu-tion and lack of convergence. Although helpful, harmonicbalance is unfortunately a compromise. Transient and DCsimulation are unsupported, and accurate active devicemodeling is still difficult.

A fourth class of simulation, Volterra-Series, has non-lin-ear capability. It is several times slower than linear nodalsimulation, and therefore at least an order of magnitudeslower than =SuperStar=. However, this is fast in relationto other non-linear simulators. Unfortunately, onlyweakly non-linear circuit simulation is accurate, and thetime-domain is unsupported. It is better suited for pri-marily linear devices, such as class-A amplifiers, than foroscillators and class-C amplifiers.

=SUPERSTAR= MODELS

We also are frequently asked “How accurate is =Super-Star=?” Because =SuperStar= is a linear simulator, accu-racy issues associated with SPICE simulation such asconvergence, iteration errors and device models, are gen-erally nonexistent. Up to a few gigahertz, when computedand measured results do not agree, it is invariably due toparasitics which have not been included in the circuitdescription. With the exception of the physical models,models in =SuperStar= are exact. However, selection ofan ideal capacitor does not include the effects of capacitorlead inductance. The user who includes inductance inseries with the capacitor achieves a level of agreement hiscolleages may not even comprehend. The responsibility ofincluding parasitics rests with the user because of the


nearly limitless variety of capacitors and because mount-ing often effects parasitics more than the part itself. Werecommend careful study of differences between com-puted and measured results to improve your knowledge ofcomponents. Some component parasitics, and potentialsolutions, are listed in Table B-1

On the left in Figure B-2 is a =SuperStar= graph for anideal three-element Chebyshev lowpass filter with a cutoffof 890 MHz. Both the insertion loss and return loss aregraphed. On the right is the same circuit, except 9 nano-henries lead inductance has been included with the twocapacitors, and 0.3 picofarads of parallel capacitance isincluded with the inductor. These parasitics have loweredthe cutoff to 610 MHz (marker 3). The insertion lossincludes transmission zeros below 890 MHz but the rejec-

PARASITIC TYPICAL VALUES REMEDIESCapacitor lead LEAD SPACING L Parallel multiple capsinductance 0.25 inches 9nH Use chip caps

0.20 inches 8nH0.10 inches 4nHLarge chip 1nHSmall chip 0.5nH

Via hole inductance 15nH*thickness(inches) Parallel multiple holes

Inductor self 2pF/inch diameter Use smaller diametercapacitance Use core

Reduce inductance

Inductor Q 40 - 200 Increase diameterAt lower freqs, use core

Inductor coupling Varies Increase spacingReorient inductorsUse toroidsUse magnetic shielding

Package modes Varies Use width < half wave-length/freqs of interest

Table B-1 Typical component parasitic and remedies. Leadlengths are assumed to be zero. Lead spacing is PWB holeseparation. Add 20nH/inch for total lead length.


tion returns to only 10 dB at 1600 MHz. The passbandreturn loss is only 9 dB at 470 MHz (marker 2). Once theseparasitics are included in the analysis, the user can findsolutions using tuning and optimization. In this case,lowering the values of the capacitors and inductors wouldhelp compensate for these parasitic effects.

Certain =SuperStar= models are exact and others, such asmicrostrip elements, use analytical expressions to modelcomponent behavior. One, two and multiport devices mayalso be described by importing S, Y, Z, G and H parameterdata directly. This is typically used for active devices, butit can be used for passive devices also, such as inductorsand transformers.

=SuperStar= models fall into three categories: exact, de-vice models, and physical transmission line models.

Figure B-2 Ideal Chebyshev lowpass (left) and lowpass withparasitics (right).


Passive Models (exact)

CAP capacitorIND inductorSLC series inductor capacitorPLC parallel inductor capacitorSFL series resonator, frequency & inductorSFC series resonator, frequency & capacitorPFL parallel resonator, frequency & inductorPFC parallel resonator, frequency & capacitorRES resistorSRX series resistor inductor capacitorPRX parallel resistor inductor capacitorPRC parallel resistor capacitorPRL parallel resistor inductorSRC series resistor capacitorSRL series resistor inductorRCLIN distributed R/L/C lineTLRLGC distributed series R-L and shunt G-C lineTLRLDC distributed series R-L and shunt D-C lineTRF ideal transformerTRFCT ideal transformer with center tapped secondaryMUI mutually coupled inductors (transformer)TLE transmission line, length in degreesTLE4 4-terminal version of 2-terminal plus ground TLE aboveTLP transmission line, physical length and KeTLP4 4-terminal version of 2-terminal plus ground TLP aboveTLX exponentially tapered, physical length and KeCPL coupled lines, electrical parametersXTL piezoelectric resonator model

Device Models (exact)

BIP bipolar transistorCCC current controlled currentCCV current controlled voltageCIR3 ideal three-port circulatorFET FET transistorDELAY block with delayGAIN gain blockGYR gyrator


ISOLATOR ideal two-port isolatorOPA operational amplifierPHASE block with phase shiftPIN PIN diodeTRFRUTH ideal Ruthroff transformerVCC voltage controlled current sourceVCV voltage controlled voltage sourceVCVS VCV with 0 ohms input and output resistance

Parameter Data (exact)

ABC direct entry of ABCD parameter dataFOU read S, Y, Z, G and H parameter four-port dataNPOn read S, Y, Z, G and H parameter data with n portsONE read S, Y, Z, G and H parameter one-port dataTHR read S, Y, Z, G and H parameter three-port dataTWO read S, Y, Z, G and H parameter two-port dataSPA direct entry of S-parameter data

Physical Models (analytical models, approximate)

ANTENNA MODELSDIPOLE dipole antenna in free spaceMONOPOLE monopole over infinite ground plane

CAPACITOR “LIKE” MODELSTFC thin-film capacitor

COAXIAL MODELSCLI coaxial lineCST coaxial stepCEN coaxial endCGA coaxial gap

INDUCTORS AND INDUCTOR “LIKE” MODELSAIRIND1 single-layer solenoid inductorRIBBON flat ribbon bond wireSPIND flat spiral inductor with no ground planeTORIND toroid inductorWIRE round bond wire


MICROSTRIP MODELSMBN microstrip bendMCP microstrip coupled lineMCN microstrip n-coupled linesMCR microstrip crossMCURVE microstrip curved lineMEN microstrip endMGA microstrip gapMIDCAP microstrip interdigital capacitorMLI microstrip lineMRIND microstrip rectangular spiral inductorMRS microstrip radial stubMSPIND microstrip spiral inductor, circularMST microstrip stepMTAPER microstrip tapered lineMTE microstrip teeMVH microstrip via hole

SLABLINE MODELS (round-rod line)RLI slablineRCP slabline 2 coupled linesRCN slabline n-coupled lines

STRIPLINE MODELS (strip between two ground planes)SBN stripline bendSCP stripline coupled lineSCN stripline n-coupled linesSEN stripline endSGA stripline gapSLI striplineSSP stripline stepSTE stripline tee

RECTANGULAR WAVEGUIDEWLI rectangular waveguideWAD waveguide adapter


TRANSMISSION LINE PHYSICAL MODELS

The physical line models allow definition of distributedcircuit elements by substrate and dimensional descrip-tion. They also provide for simulation of line discontinui-ties. These models are approximate, but provide usefulsimulation for a wide range of parameter values throughmicrowave frequencies. Parameter limits for accurateresults and the references used are given for each modelin the Reference chapter.

Users may choose between electrical and physical trans-mission line descriptions. At microwave frequencies, de-scription via purely electrical parameters is insufficient toinsure the best available accuracy. For example, the cas-cade of 33 and 75 ohm lines is ideally modeled via simpleand exact formulae. However, at higher frequencies, thisideal view ignores 1) the parasitics of the step in width, 2)dispersion in microstrip, and 3) radiation from the struc-ture. The effects of each of these increase with frequency.

The step parasitics are modeled by an equivalent circuitat the discontinuity. The user specifies three elements forthis cascade; a 33 ohm line, a microstrip step, and a 75 ohmline. =SuperStar= computes the values of the step modeland includes them in the simulation.

Dispersion occurs in microstrip because portions of thefields are in different dielectric media. The characteristicimpedance and effective dielectric constant are functionsof frequency. Dispersion is automatically considered in=SuperStar= microstrip physical models. Dispersion isinsignificant in coax and stripline. In microstrip, thinnersubstrates increase the frequency at which dispersionbecomes a factor.

Radiation exists in “unbound” lines, such as microstrip,and is greatest in unterminated structures, such as openstubs and resonators. One of the more hideous conse-


quences is the launching of propagating waves in thehousing. These waves may be received later, adding vec-torially with the desired path, causing passband rippleand stopband peaks and notches. Radiation is not mod-eled by circuit simulators. Proper packaging design re-duces these effects. If possible, package dimensionsshould be less than half a wavelength at the highestfrequency of interest.

PHYSICAL MODEL EXAMPLE

Consider the microstrip transmission line transformer inFigure B-3. It is designed to match a 50 ohm microstripline to 200 ohms from 2000 to 4000 MHz. The substrateis 1.778 mm (70 mils) thick PTFE. 200 ohms is an extremeimpedance for microstrip which exaggerates the need forphysical modeling.

The circuit is first described via electrical line models andthe steps are ignored. This circuit is displayed in the leftwindow in Figure B-4. The circuit described with physicalmodels and steps is displayed in the right window.

The electrical model is almost ideal; line loss is includedbut microstrip dispersion and step discontinuities areignored. The line impedances and lengths were optimizedusing the electrical model. The physical model was thenadded with line dimensions which matched the electricalmodel line impedances and lengths at 3000 MHz.

Figure B-3


The ELECTRICAL window in Figure B-4 shows a worsecase return loss of 30dB across the octave band with theoptimized electrical model. The physical model return lossis worse by 4dB at 4000 MHz. The physical model moreaccurately predicts the actual constructed circuit re-sponse. Later we will optimize the network to correct fordiscontinuities.

WHEN ARE PHYSICAL MODELS INDICATED?

When are physical models required? The following guide-lines may be used to augment your experiences. Condi-tions which suggest using physical models:

Higher frequenciesNarrow bandwidth applicationsHigher return loss specificationsBandpass and bandstop filters

Figure B-4


Large stepsAcute or square cornered bends

Conditions which reduce the need for physical models are:

Lower frequenciesBroadband applicationsLower return loss specificationsSmall stepsObtuse or chamfered circuit bends

In this case, “higher frequencies” means above 4000 MHz.Below a few gigahertz, physical models are rarely re-quired. In general, =SuperStar= models are highly accu-rate to about 12000 MHz, and are useful to about 18000MHz, particularly with thinner substrates. Use of ana-lytical models above 18 GHz is only recommended for verythin substrates.

Figure B-5


The degree and combination of these cases indicatewhether physical models are required. For example,physical models may be unnecessary in broadband ampli-fiers above 4000 MHz, but narrow filters may requirephysical models even below 4000 MHz.

To illustrate the effect of frequency, consider Figure B-5.The matching network has been simply scaled higher infrequency by a factor of three to 6000 to 12000 MHz. Theelectrical and physical models are given on the left andright, respectively. By 9000 MHz the electrical model hasdeveloped serious accuracy problems and use of physicalmodels is highly recommended.

PHYSICAL MODEL EXECUTION SPEED

While physical models enhance simulation accuracy athigher frequencies, they execute slower than electricalmodels. For some models, the difference is significant.The slowest execution occurs with the microstrip line andmicrostrip coupled line models. Accurate closed form ex-pressions to model microstrip are complex. Stripline, coaxand slabline are faster.

RELATED PHYSICAL DIMENSIONS

Physical model dimensions are often dependent. For ex-ample, in the previous example the step dimensions arenaturally equal to the widths of the adjacent lines. Tuningand optimization are facilitated by using the EQUATEblock to define and equate dimensions.

OPTIMIZED PHYSICAL MODEL

In Figure B-6 the 6000 to 12000 MHz microstrip trans-former has been optimized to compensate for the effects ofthe steps and dispersion. The compensation is inexact,butthe worse case return loss across the band is similar in thefinal physical model and the ideal electrical model.


Figure B-6 Microstrip transformer electrical (left) and moreaccurate physical (right) analyses.


Appendix C

Drivers

W riting =SuperStar= circuit files from within otherprograms is easy, and creates a powerful environ-ment for circuit design. If you have developed

in-house programs to design specified circuits, you caneasily modify those programs to write =SuperStar= textnet lists. =SuperStar= then displays responses and allowsyou to tune, optimize or perform statistical analysis.

Included with =SuperStar= is source for a BASIC programEDGEFILT.BAS. This program designs Chebyshev half-wavelength edge coupled transmission line resonatorbandpass filters. It is provided to illustrate how to writeapplication drivers for =SuperStar=. A driver synthesizesa circuit and writes a circuit file for =SuperStar=. Theedge coupled half-wavelength bandpass filter equationsused in EDGEFILT.BAS are given on pages 296 to 298 ofHF Filter Design and Computer Simulation, Noble Pub-lishing, phone (770) 908-2320. The equations used tocompute the Chebyshev prototype values are given onpage 30 of the same reference.

This filter design is suitable for bandwidths up to about15%. Chapter 10 of the reference contains a design forwider bandwidths. This program computes the length ofthe coupled lines for air.

SOURCE CODE

The provided source code is compatible with QBASIC,Microsoft QuickBASIC and other Basics. The code con-tains only 147 lines. Approximately 80% of the code isused to format the screen and get inputs. Only 23 linesare used to write the =SuperStar= file.

Eagleware Corporation has released copyrights on thesource code in EDGEFILT.BAS. It may be used in wholeor part, modified or unmodified, for the development ofother =SuperStar= drivers, without further approval.This release, in no way, affects copyrights on other Eagle-ware products.

CODE DESCRIPTION

Define and dimension program variables and clear the screen.

Generate the opening credit screen.

Erase the normal Basic and write the new 25th screen line.

Detect the function keys and initiate Design, Write File or End.

Generate the design screen border with titles.

Get user inputs. The method used remembers the last valueentered. Simply hit the enter key to use the last value.

Compute lowpass to bandpass transform variables.

Compute Chebyshev lowpass prototype “G” values.

Compute Even and Odd mode impedances of coupled lines.See page 298 of HF Filter Design and Computer Simulation.

Return for next design, write file or quit.

Get desired name of =SuperStar= file.

Write file: Computes the length of 1/4 wavelength in millime-ters in air. Placing the coupled lines “end to end” creates 1/2wavelength resonators. Establish the frequency scale. Returnfor next design, write file or quit.

354 Drivers

PIMATCH DRIVER

Listed below is another example of a =SuperStar= driver.It designs simple three element pi matching networks.The network matches an input resistance (on the left) toan output resistance (on the right), with user selected Q.This and other matching networks are described in Mo-torola Application Note AN-721, “Impedance MatchingNetworks Applied to RF Power Transistors”, by B. Bec-ciolini.

This driver uses a simple parameter input scheme withoutmuch screen design or formatting. The entire program isonly 49 lines long.

The =SuperStar= circuit file written by the program isPIMATCH.CKT. The match provided by this simple cir-cuit is perfect at the design frequency. =SuperStar=analysis provides the match versus frequency.

Drivers 355

REM *** Pi MATCH =SuperStar= DRIVER ***SCREEN 0REM *** INPUT DATA ***INPUT “Frequency (MHz)”; FREQOMEGA = 2 * 3.141593 * 1000000! * FREQINPUT “R input (ohms)”; RININPUT “R output (ohms)”; ROUTIF ROUT RIN THEN

QMIN = SQR(ROUT / RIN - 1)ELSE

QMIN = SQR(RIN / ROUT - 1)END IFPRINTGetQ:PRINT “Minimum Q is” + STR$(QMIN) + “.”PRINT “Enter a larger value.”INPUT “Q”; QIF Q <= QMIN THEN GOTO GetQIF RIN > ROUT THEN

A = QELSE

A = SQR(RIN / ROUT * (Q * Q + 1) - 1)END IFREM *** COMPUTE VALUES ***XCAA = RIN / AXCCC = ROUT * SQR((RIN / ROUT) / (A * A + 1 - RIN / ROUT))XLBB = (A * RIN + RIN * ROUT / XCCC) / (A * A + 1)CAA = 1 / (OMEGA * XCAA)LBB = XLBB / OMEGACCC = 1 / (OMEGA * XCCC)REM *** COMPUTE FREQUENCY SCALE FOR SWEEP ***DELTA = 1.25 * FREQ /QIF DELTA = FREQ THEN DELTA = FREQREM *** WRITE PIMATCH.CKT FILE ***OPEN “PIMATCH.CKT” FOR OUTPUT AS #1PRINT #1, “CIRCUIT”PRINT #1, “CAP 1 0 C=”; MID$(STR$(1E+12 * CAA), 2)PRINT #1, “IND 1 2 L=”; MID$(STR$(1E+09 * LBB), 2)PRINT #1, “CAP 2 0 C=”; MID$(STR$(1E+12 * CCC), 2)PRINT #1, “DEF2P 1 2 PIMATCH”PRINT #1, “WINDOW”PRINT #1, “PIMATCH(”; MID$(STR$(RIN), 2); “,”; MID$(STR$(ROUT), 2); “)”PRINT #1, “GPH S21 -50 0"PRINT #1, ”GPH S21 -1 1"PRINT #1, “SMH S11"PRINT #1, ”FREQ"PRINT #1, “SWP” + STR$(FREQ - DELTA) + STR$(FREQ + DELTA) + “ 51"CLOSEEND

Table C-1

356 Drivers

Appendix D

SCH2CKT Program

In the event that you need to create a text circuit file fromyour schematic for unusual customization, or need a partslist of your schematic, Eagleware has created a programcalled SCH2CKT. This program accepts a schematic fileand writes the equivalent circuit text file.

SCH2CKT must be run from a DOS prompt and is locatedin the EAGLE\BIN subdirectory. To run SCH2CKT, firstgo to the EAGLE directory in DOS. Next, enter:

BIN\SCH2CKT schfile [cktfile]

where schfile is the name of the schematic file (extension.SCH is added if no extension is specified). and cktfile isoptional and is the name of the resultant circuit text file.If cktfile is not specified, the name specified for schfile isused with the extension changed to *.CKT.

Appendix E

Version 3.4 Files

This appendix covers the old circuit file format used in=SuperStar= Version 3.4 and earlier.

We recommend using the Version 6.0 file structure forall new files which you create. It is easier, more com-prehensive and shorter than the older format. In thefuture, the older format may be unsupported.

RUNNING VERSION 3.X FILES

To run an old file you may simply type the word OLD afterthe word CIRCUIT in the file and edit the OUTPUT block,changing it to the new WINDOW block format.

A utility program is included which automatically con-verts old files. To run this utility, at the DOS prompt inthe EAGLE directory, type

BIN\CONVERT filename

where filename is the name of the old file. If no extensionis specified for filename, .CKT is assumed. CONVERT willsave your old file with the extension .OLD and then it willconvert your circuit to a .CKT file. If an extension isspecified, that extension is used for the converted file.

In =SuperStar= you may open and analyze your convertedcircuit by selecting “Open *.CKT (Text) file” from the Filemenu and then typing the filename in the dialog box.

Upon viewing the file in the editor, you will notice that thecircuit block is the same, however the word OLD mustfollow the word CIRCUIT in the first line. Also, the OUT-PUT blocks and the FREQ blocks are now consolidatedinto one window specification. Refer to Chapter 4,WindowBlocks, for information on the window specification.

360 Version 3.4 Files

Appendix F

References

[1] Ralph S. Carson, High-Frequency Amplifiers, JohnWiley & Sons, New York, 1982.

[2] Jerome L. Altman, Microwave Circuits, D. Van Nos-trand, Princeton, NJ, 1964.

[3] Application Note 95, S-Parameters-Circuit Analysisand Design, Hewlett-Packard, Palo Alto, CA, September1968.

[4] Application Note 154, S-Parameter Design, Hewlett-Packard, Palo Alto, CA, April 1972.

[5] V. Rizzoli and A. Lipparini, “Computer-Aided NoiseAnalysis of Linear Multiport Networks of Arbitrary Topol-ogy,” IEEE Trans. MTT-33, No. 12, December 1985.

[6] H. Hillbrand and P. Russer, “An Efficient Method forComputer Aided Nose Analysis of Linear Amplifier Net-works,” IEEE Trans. Circuits Syst., Vol. CAS-23, April1976.

[7] H.A. Watson, ed., Microwave Semiconductor Devicesand Their Circuit Applications, McGraw-Hill, New York,1969, pp. 271-278.

[8] Lloyd P. Hunter, ed., Handbook of Semiconductor Elec-tronics, 3rd edition,McGraw-Hill,New York,1970,pp.11-3to 11-19.

[9] H.E. Green, “The Numerical Solution of TransmissionLine Problems,” Advances in Microwaves, Vol. 2,AcademicPress, New York, 1967, pp. 327-393.

[10] K.C. Gupta, et al., Computer-Aided Design of Micro-wave Circuits, Artech House, Dedham, Massachusetts,1981, pp. 131-134.

[11] P.I. Somlo, “The Computation of Coaxial Line StepCapacitances,” IEEE Trans. MTT, Vol MTT-15, January1967, pp. 48-53.

[12] W. Alan Davis, Microwave Semiconductior CircuitDesign, Van Nostrand Reinhold, New York, 1984, pp. 118-119.

[13] P. Wolf, “Microwave Properties of Schottky-barrierField-effect Transistors,” IBM Journal of Research andDevelopment, March 1970, pp. 125-141.

[14] “Device Modeling,” Avantek Microwave Semiconduc-tors: GaAs and Silicon Products, Avantek, Santa Clara,1989, pp. 8-12 to 8-13.

[15] M. Kirshning, et al., “Measurement and Computer-Aided Modeling of Microstrip Discontinuities by an Im-proved Resonator Method,” MTT-S Digest, 1983, pp.495-497.

[16] M. Kirshning, et al., “Accurate Wide-Range DesignEquations for the Frequency Dependent Characteristicsof Parallel Coupled Microstrip Lines,” IEEE MTT-32,1984, pp. 83-90. Errata, MTT-33, 1985, p. 288.

[17] Rolf H. Jansen, “High-Speed Computation of Singleand Coupled Microstrip Parameters Including Dispersion,High-Order Modes, Loss and Finite Strip Thickness,”MTT-26, 1978, pp. 75-81.

362 References

[18] M.V. Schneider, “Microstrip Lines for Microwave Inte-grated Circuits,” The Bell System Technical Journal, May-June 1969, pp. 1421-1444.

[19] E.O. Hammerstad, “Equations for Microstrip CircuitDesign,” Proc. 5th European Microwave Conference, Ham-berg, 1975, pp. 268-272.

[20] P. Benedek and P. Silvester, “Equivalent Capacitancefor Microstrip Gaps and Steps,” IEEE MTT-20, November,1972, pp. 729-733.

[21] R. Jansen and M. Kirschning, “Arguments and anAccurate Model for the Power-Current Formulation ofMicrostrip Characteristics Impedance,” AEU, Band 37,1983, Heft 3/4, pp. 108-112.

[22] Harold A. Weeler, “Transmission-Line Properties of aStrip on a Dielectric Sheet on a Plane,” IEEE MTT-25,1977, pp. 631-647.

[23] H. Atwater, “Microstrip Reactive Circuit Elements,”IEEE MTT-31, June 1983, pp. 488-491.

[24] J.P. Vinding, “Radial Line Stubs as Elements inStripline Circuits,” NEREM Rec., pp. 108-109, 1967.

[25] A. Farrar and A.T. Adams, “Matrix Methods for Mi-crostrip Change in Width and Cross-Junctions,” IEEEMTT-20, August 1972, pp. 497-504.

[26] A. Gopinath, “Equivalent Circuit Parameters of Mi-crostrip Change in Width and Cross-Junctions,” IEEEMTT-24, March 1976, pp. 142-144.

[27] M.E. Goldfarb and R.A. Pucel, “Modeling Via HoleGrounds in Microstrip,” IEEE Microwave and GuidedWave Letters, Vol. 1 No. 6, June 1991, pp. 135-137.

[28] G.B. Stracca, G. Macchiarella and M. Politi, “Numeri-cal Analysis of Various Configurations of Slab Lines,”MTT-34, No. 3, March 1986, p. 359-363.

References 363

[29] H.M. Altschuler and A.A. Oliner, “Discontinuities inthe Center Conductor of Symmetric Strip TransmissionLine” IRE MTT-8, May 1960, pp. 328-339.

[30] Seymour B. Cohn, “Shielded Coupled-Strip Transmis-sion Line,” MTT-3, 1955, pp. 29-38.

[31] S.B. Cohn, “Characteristic Impedance of ShieldedStrip Transmission Line,” MTT-2, 1954, pp. 52-55/

[32] H.A. Wheeler, “Transmission Line Properties of aStripline Between Parallel Planes,” MTT-26, 1978, pp.866-876.

[33] I.J. Bahl and R.Garg, “A Designer’s Guide to StriplineCircuits,” Microwaves, Jan. 1978, pp. 90-96.

[34] Private phone conversation between R.W. Rhea andI.J. Bahl, October 1987.

[35] N. Marcuvitz, Waveguide Handbook, Peter PeregrinusLtd., London, 1986.

[36] Phillip H. Smith, “Transmission Line Calculator,”Electronics, Vol. 12, Jamuary 1994, p. 29.

[37] Phillip H. Smith, Electronic Applications of the SmithChart, 2nd edition, Noble Publishing, Atlanta, 1995.

[38] Guillermo Gonzales, Microwave Transistor Amplifi-ers: Analysis and Design, 2nd edition, Prentice-Hall, NewYork, 1997.

[39] H.C. Miller, “Inductance Formula for a Single-LayerCircular Coil,” Proc. IEEE, Vol. 75, pp. 256,257, 1987.

[40] R.G.Medhurst, “H.F.Resistance and Self-Capacitanceof Single-Layer Solenoids,” Wireless Engineer, pp. 80-92,1947.

[41] C.A. Balanis, Antenna Theory: Analysis & Design,John Wiley & Sons, New York, 1982, pp. 292-295.

364 References

[42] A. Weisshaar and V.K. Tripathi, “Perturbation Analy-sis and Modeling of Curved Microstrip Bends,” IEEE MTT,Vol. 38(10), 1990, pp. 1449-1454.

[43] S.S. Gevorgian, et.al., “CAD Models for MultilayeredSubstrate Interdigital Capacitors,” IEEE MTT-44, 1996,pp. 896-904.

[44] F.W. Grover, Inductance Calculations, Dover Publica-tions, Inc., New York, 1962.

[45] J.I. Smith, “The Even- and Odd-Mode CapacitanceParameters for Coupled Lines in Suspended Substrate,”IEEE MTT-19, 1971, pp. 424-431.

[46] R.L. Remke and G.A. Burdick, “Spiral Inductors forHybrid and Microwave Applications,” Proc. 24th ElectronComponents Conf., 1974, pp. 152-161.

[47] C.R. Burrows, “The Exponential Transmission Line,”Bell System Technical Journal, Vol. 37, 1938, pp. 555-573.

[48] R.E. Collin, Field Theory of Guided Waves, McGraw-Hill, New York, 1960, pp. 185-195.

[49] H.M. Greenhouse, “Design of Planar RectangularMicroelectronic Inductors,” IEEE Trans. Parts, Hybrids,and Packaging, PHP-10(2), June 1974, pp. 101-109.

[50] B.C. Wadell, Transmission Line Design Handbook,Artech House, Boston, 1991.

[51] C.L. Ruthroff, “Some Broad-Band Transformers,”Proc. IRE, Vol. 47, 1959, pp. 1337-1342.

[52] D.M. Krafcsik and D.E. Dawson, “A Closed-Form Ex-pression for Representing the Distributed Nature of theSpiral Inductor,” 1986 Microwave and Millimeter-WaveMonolithic Circuits Symposium, 1986, pp. 87-92.

References 365

Appendix G

Error Messages

SuperStar= is capable of detecting many different er-rors. When =SuperStar= detects an error, a messageis displayed to assist the user in determining the

cause. Most error messages are the result of a syntax errorin the circuit file detected during translation before re-sponse calculation occurs. Other errors may result atrun-time which are the result of an unresolvable mathexception. This may be caused by an undetected syntaxerror in the circuit file, an improper circuit description, ora command which cannot be completed.

RED ERROR BAR

The red error bar appears at the bottom of the screen whenany mathematical computational error occurs, such asdividing by zero. Check your circuit file for this type oferror and retranslate your circuit.

DISPLAYED ERROR MESSAGES

There are three types of error messages.

(a) Errors occuring during translation

(b) Warnings occuring during translation

(c) Nontranslation errors

ERRORS DURING TRANSLATION

=SuperStar= automatically displays errors occuring dur-ing translation. Translation occurs after pressing F9 fromthe editor, or selecting “Translate, Loading Values FromEditor” in the Tuning Menu. If one or more error messagesare displayed during translation,the text/schematic editorshould be used to fix the problems.

A node number was expected where __ was found, lineThis error occurs on a component line. Check the linenumber and change the indicated string to a node numberin the editor.

All window blocks must have at least one output requestThe window block does not contain an output request(GPH, SMH, POL, etc.).

Ambiguous keyword __ on line __You have abbreviated the title of a component value to anambiguous name, such as NA for NARROW or NAME.

Bad code (__) at line __This code is unrecognizable.

__ can only be used with tabular output (DSP) at __Certain parameters, such as SPAR or YPAR, can only beused on a DSP window.

__ can only be used with 2-port data at __.Some output parameters, such as circles and noise, areonly valid for two port data.

Cannot find RX data at __. The name may need a full pathsuch as C:\EAGLE\EXAMPLES\ANTENNA.RXThe file specified was not found in the default directory, orthe one specified. Check the filename to ensure that thefull path is given.

368 Error Messages

Cannot find S or Y-parameter device data file __. Checkfilename. The name may need a full path such asC:\EAGLE\EXAMPLES\MRF901.615 or C:\SDATA\MO-TOROLA\2NXXXX\2N6618A.A03The S- or Y-parameter file specified on a TWO code linewas not found. Check the filename. Check that the fileexists in the default or specified directory. The filenamemay need to include a pathname.

Cannot graph __ on a polar chart at __.The requested parameter is real, not complex, and cannotbe plotted on a polar chart.

Cannot graph __ on a Smith Chart at __.The parameter has no meaning on a Smith Chart.

Cannot have text following a block label (__) at __The label specified cannot have text following it on thesame line. A return should be inserted immediately fol-lowing the label.

Circuit and equation blocks may only be used before orin the first window specification.A circuit or equation block was written in a window blockother than the first window block. Change the circuit file.

Combined responses must have the same number ofports at __.Post processing cannot be used to combine networks withdifferent numbers of ports.

Combined window responses must have identical fre-quency ranges at __When using the post processor to combine window re-sponses, the same frequency range must be used for allwindows involved.

Error Messages 369

Component name __ defined twice, line __The component specified has been defined twice. Renamethe second component (on the specified line).

Data in file __ does not cover the analysis frequencyrange. The data has been extrapolated.The data file does not contain data at low or high enoughfrequencies. The extrapolation may not be valid for thegiven device.

Default sweep value was specified (with “@”), but onlyone sweep line was used at __.A default sweep value has no meaning if only one sweepline is used.

DEF__P cannot be used before a network has beendefined at __Circuit elements must be given before the DEFnP line.

Duplicate window name at __Two windows have the same name. Rename one window.

Each optimize line must start with two frequencies(LOWER UPPER) at __The specified line does not contain two frequencies. Makesure that both lower AND upper frequencies have beenspecified. For outputs like SWP, a third number is alsorequired.

Equations are available in =SuperStar= Professionalonly at __. (Variable or invalid number __ was used.)A variable was found on the specified line,but the detectedkey is not authorized for =SuperStar= Professional.

Extra parameters ignored at __Too many parameters were given.

370 Error Messages

FUNCTION Parameter __ is declared twice at __The FUNCTION declaration has two or more parameterswith the same name.

FUNCTION _ is declared twice (first declaration was at )The same FUNCTION name has been reused.

If three sweep lines are used, the last line must specifya frequency sweep at __.The only time that three lines can be used in a frequencysweep is to sweep two parameters on a 3D graph. Thethird line must then specify the frequency to use.

If 3D graphs are used, two sweep lines must be specified3D graphs require at least two sweeps, one frequency andone parameter.

Incorrect form for designator at __This error occurs for old circuit files written in Versions3.X of =SuperStar=. An invalid form for a two-port desig-nator was used.

Incorrect form for IF-THEN statement at __An IF-THEN statement in the EQUATE block had anincorrect format.

Incorrect function at (__) at __=SuperStar= is expecting a function such as SIN(x) orCOS(x). The indicated function is not valid.

Incorrect function call __ at __The syntax is invalid or the function name is unknown.

Incorrect number of parameters sent to FUNCTION __The number of parameters used does not match thenumber of parameters in the FUNCTION declaration.

Error Messages 371

Incorrect number of parameters sent to MODEL __ at __The number of parameters used does not match thenumber of parameters in the MODEL definition.

Incorrect number of noise parameters on a line in datafile __. Each frequency must include an additional fourparametersThe data file does not contain complete noise data on thespecified line. See Chapter 5 for more information.

Incorrect number of numeric fields at __Check the line for the correct number of values for the part,such as CAP should have at least one value for the capaci-tance and two if an optional Q is used.

Incorrect number of parameters at __.Check to see that the parameters are as expected.

Incorrect number of RX parameters on a line in data file__. Each frequency must include two additional parame-ters.The data file does not include complete RX data on thespecified line. See Chapter 5 for more information.

Incorrect number of S-Parameters in data file __. Eachfrequency must include the correct number of parame-ters with spaces between each as the delimiter.Each line in an S- or Y-parameter data file must have ninenumbers. One for the frequency in megahertz and eightfor the magnitudes and angles. See Chapter 5 for details.

Incorrect use of an output grid at __The output grid commands, DSP, GPH, LOG, POL andSMH have been used in an incorrect sequence, such as aGPH followed by a SMH.

372 Error Messages

Invalid DEFnP line for MODEL at __The DEFnP name should match the model name. Also,check the number of nodes, it should match the DEFnP .

Invalid EQUATE statement at __There is a syntax error in the EQUATE statement.

Invalid FUNCTION declaration at __There is a syntax error in the FUNCTION declaration.

Invalid graph range at __The graph range used does not have the right number ofparameters.

Invalid GOTO statement at __There is a syntax error in the GOTO statement.

Invalid LABEL statement at __There is a syntax error in the LABEL statement.

Invalid MODEL declaration at __There is a syntax error in the MODEL declaration.

Invalid number (__) found at __This error occurs in the equation block. =SuperStar= islooking for a number that is not present.

Invalid operator (__) at __Only valid operators may be used, such as “+”, “-”, “*”, etc.

Invalid or unknown parameter name (__) at __.Check to see that the parameter name is valid.

Invalid use of DEFnP at __. Valid Examples: DEF2P 1 5NAME, DEF4P 1 4 3 5 COUPLERThe DEF2P code must contain two nodes and a name forthe network. Check the indicated line.

Error Messages 373

Invalid use of not operator (~) at __The not operator is a unary operator and must precede thevalue to operate on.

Invalid window description at __The line following the WINDOW line must contain thename of the network and the input impedance in paren-theses. Check the indicated line.

Label __ has already been defined at __A Label can only be used once.

Label is too long at __Label names can only be twelve characters.

Maximum node number is 9999 at __.Only use node numbers between 0 (ground) and 9999.

Maximum number of frequencies is __, at __A FREQ block has tried to use more than the maximumallowed frequency points..

Maximum number of lines in the window’s output sectionis 1 if DSP is usedWhen DSP is used in the WINDOW, the output descriptionis complete. No additional lines are required or allowed.

Maximum number of ports is __ at __Too many ports have been used on the specified line.

Maximum number of sweep lines per window is __ at __.You have specified too many sweep lines. In most cases,only one is needed.

Maximum number of variable substitutions into circ. isMore than the allowed number of variables have been usedin the CIRCUIT block.

374 Error Messages

MInimum number of frequencies is __, at __The line did not request enough frequency points.

Minimum number of frequencies per log decade is 1 atEach decade in a logarithmic frequency sweep may con-tain 1 or more frequency points. See Chapter 4.

Missing parameter name at __.A parameter name was not given.

MODEL __ is declared twice (first declaration was at __)The model name specified has already been defined.

MODEL declarations must end with a DEFnP line at __All models must declare the equivalent circuit followed bya DEFnP line.

MODEL declarations must only have one DEFnP line,andno text may follow the DEFnP line at __A possible cause of this is forgetting to put a block label

MODEL Parameter __ is declared twice at __The MODEL declaration has two or more parameters withthe same name.

Multiple coupled lines must have an even number ofnodes on __The line does not have the right number of nodes.

No device data specified on two port code __A TWO call was made but a filename and correct path-name were not specified, or the name was invalid.

No frequency code given at __A valid output request (GPH, SMH, etc.) was not found inthe WINDOW block.

Error Messages 375

No noise data found in file __. We have assumed the datato be passive.If you intend to use a device for noise analysis, you shouldensure that the data file contains noise data.

No optimization parameters were specified at __An OPT block was found,but does not contain any parame-ters for optimization.

No parameter given to graph at __A parameter was expected but not found.

Noise figure is only available in =SuperStar= Profes-sional at __A circuit file with noise figure output specifications wastranslated in =SuperStar=. Noise figure is available in=SuperStar= Professional only. Call Eagleware if youwant to upgrade your =SuperStar= Professional.

Normal and 3D graphs should not be used in the samewindow at __.A WINDOW block cannot contain both normal (eg, GPHor SMH) and 3D graphs (G3D or L3D).

__ only contains __-port data so __ cannot be displayedFor instance, S32 cannot be displayed for a 2-port.

Only one frequency sweep can be specified at __.The FREQ block can only contain one frequency sweep.

Only one default can be specified on a sweep line at __.Multiple default points (@) were found on a sweep line.

Only one scale can be used per Smith Chart at __.A Smith Chart can only have one scale. If two traces usethe same Smith Chart, then either they must use the samescale or one of them must autoscale (no scale given).

376 Error Messages

Operator __[] can only be used with circles.Operator __[] can only be used with complex quantities.Operator __[] can only be used with gain circles.Operator __[] can only be used with noise circles.Operator __[] can only be used with stability circles.The given operator can only be used with the given type.For example, RAD can only be used with circles (to findthe radius).

Optimization frequencies are outside the sweep fre-quency range, __One or more lines in the OPT block specify frequencies notwithin the sweep range. Increase the frequency sweeprange or reduce the optimization frequency range. Theerror line number may be a line in the FREQ or OPT block.This also may result from precision ambiguity.

Optimization frequencies do not cover any analysispoints at __. (Requested __ to __, but nearest points are__ and __.)The frequency range requested for optimization is withinthe sweep range, but the discrete points do not lie on thesweep points.

Optimization operator not found in “__” at __. Operatormust be =,<,>, or %.Valid optimize operators are =, >, < and %.

Physical model codes are only available in =SuperStar=Professional at __A circuit file with physical models present was translatedin =SuperStar=. Physical models are available in =Super-Star= Professional only. Use electrical line models, or callEagleware to upgrade to =SuperStar= Professional.

Error Messages 377

Physical model used before a substrate was definedA SUB line must precede any physical model (microstrip,stripline, waveguide, and coax). See Chapter 12, Refer-ence, for information on writing a SUB line.

The line immediately following window must define thewindow, at __The line following the WINDOW line must contain thename of the network and the terminations in parentheses.

Too few parameters in part __More parameters must be specified for the indicated part.

Too few parameters on __More parameters must be specified on the indicated line.

Too many display items (i.e. GPH or SMH) requestedMore than 4 outputs were requested in one WINDOWblock at the specified line.

Too many DSP items requested at __Make another WINDOW block if you need to display all ofthe items simultaneously.

Too many nodes (__) used at line __. Limit is __.Too many nodes were used in one CIRCUIT block.

Too many parameters on __There are too many parameters on the indicated line.

Too many SUB lines used (limit is __). Use NAME toreuse substrates.Too many SUB lines were used in the CIRCUIT block. Trydefining one, naming it, and reusing it elsewhere.

378 Error Messages

Undefined variable __ or incorrect mathematical func-tionA variable was used in the CIRCUIT or EQUATE blockswhich hasn’t been assigned a value.

Undefined variable __ or incorrect mathematical func-tion during MODEL expansion at __An undefined variable was found inside a MODEL decla-ration. Edit the model to fix the problem.

Undefined window reference at __When using the post processor to combine window re-sponses, a reference to a window that does not exist hasoccurred.

__: Unknown label in equation blockA label was specified by a GOTO which was not defined.

Unknown network name used (__) in net component.Name all blocks with the name of the referred network.A NET was found, but the network referred to does notexist. Make sure the name is correct.

Unknown variable or invalid number __ at __Check the spelling for a variable, or make sure that theletter O is not used for a zero (0).

Unmatched parentheses at __Unmatched opening or closing parentheses were found.

Unrecognized circuit code at __A circuit code was specified which was unrecognized. Thisis often simply a typographical error.

Unrecognized frequency code (__) at __Frequency sweep codes are DIS, SWD, SWL and SWP.

Error Messages 379

Unrecognized keyword (__) on line __The command indicated is not a =SuperStar= keyword.

Unrecognized keyword (__) on line __. Note: TWO, THR,FOU, and NPO no longer use the Zo and Option key-words. You must now use a # line in the data file (eg, “#MHZ S MA R 50").These codes were changed with Version 6.0.

Unrecognized optimize parameter (__) at __An unrecognized parameter or weight was specified in theOPT block. Refer to Chapter 6, Optimization.

Unrecognized option (__) on line __An option was specified which was unrecognized.

Unrecognized output code at __Valid codes are DSP, GPH, LOG, POL, SMH, G3D, andL3D.

Variable name is too long at __EQUATE variables can have a maximum of 11 characters.

Warning! long and short (i.e., “r=50" and ”50") MixedThe labels on the part values in the circuit file are mixed:some are long and some are short. It is helpful to namethe circuit part values in a consistent format. This isespecially recommended for new users.

Warning: Old style optimization weight parameter (__)ignored at __. Use the new @ form (e.g., S11<-30@100,where the weight is 100).Starting with Version 6.0, a new weight format is used.

Window names may contain only alpha and underscoresSelf explanatory.

380 Error Messages

=SUPERSTAR= OPERATION ERRORS

If an error occurs when =SuperStar= is not translating afile, such as during optimization or Monte Carlo analysis,an error window will be displayed stating the error.

Errors detected by =SuperStar= outside of translation arelisted below in alphabetical order.

All windows must have a frequency block.The FREQ block is missing from the circuit file.

An attempt was made to cascade a part which must benodally connected __.

An attempt was made to cascade an undefined two- portAn attempt was made to parallel interconnect a part

which must be nodally connected, __An attempt was made to series interconnect a part which

must be nodally connected, __.These errors may occur in Version 3.X files only. See yourolder manual for details.

Disk error while saving file. Original file (if any) has beensaved with a *.BAK extension.Self explanatory.

Equations are available in =SuperStar= Prof. only.A circuit file with equations present was translated in=SuperStar=. Equations are available in =SuperStar=Professional only. Call Eagleware if you wish to upgradeto =SuperStar= Professional.

Error in file TEMPLATE.TXT: No templates found.This should only occur if TEMPLATE.TXT is corrupt.

Error in format (#) line of S-parameter data file.The line beginning with “#” of the specified S-parameterdata file is invalid. Check this line in the S-parameter file.

Error Messages 381

FUNCTIONs nested too deeply (__ levels maximum).Current function is __.Check to see that you have not used a recursive function(a function that calls itself).

G and H Parameter files can only be used for loadingtwo-port data in data file __.G and H parameters are undefined for other numbers ofports (eg, 1 or 3).

Internal X1G, X2G, or X12 error. This results during noiseanalysis. Null parts are used to correct the problem.Please contact Eagleware for assistance.Self explanatory.

Libraries nested too deeply (__ levels maximum). Cur-rent filename is __.Check to see that you have not used a file that loads itself.

Library file __ is too large. Maximum size is __ charac-ters; this file is __ characters.Split the library into two or more files.

No circuit file in buffer.No circuit file is loaded.Load a circuit file.

No filename given. Unable to create initial Monte Carlosetup.A circuit file must be saved with a name before performingMonte Carlo analysis. Select “Save As” in the File menu.

No format line (#) found in data file __. We are assumingthis data file to be in MHz, __ Parameter, __, %lg ohm.Please add a format line to the data file.In Version 6.0, all data files must have a format line.

382 Error Messages

No OPT block in circuit file.An OPT block must be created in the circuit file beforeoptimization is possible.

No samples met yield criteria. Either Restart with slowersetting or use Monte Carlo Setup to either change com-ponent tolerances or increase the number of samples.Yield optimization must find at least one sample whichmeets the yield criteria.

No values are marked for optimization.No values are marked for tuning.Values to tune or optimize must be preceded by a “?”.

NOD command used before using CON. This is generallycaused by any incorrect circuit topologies, such as anode with only one lumped element connected to it.This error usually occurs in Version 3.X files only. SeeAppendix D for information on writing Version 3.X files.

Substrates can only be edited when a schematic isloaded.In a text file, use a SUB command to add a substrate.

The circuit buffer is empty, so translation was not in-voked.No circuit file is loaded to translate.

The current window cannot be plotted.Windows containing DSP output and other text windowsmay not be plotted.

This circuit file has not yet been saved, doesn’t have aname, and therefore cannot be reloaded.Self explanatory.

Error Messages 383

Translation was not invoked: all files require frequency,circuit, and window blocks.The circuit file is missing a FREQ, CIRCUIT or WINDOWblock.

Two or more format (#) lines found in data file __.Data files can only contain one format line.

Unknown error messageThis error is displayed if no other error messages willdescribe what has occurred. If this happens, please callEagleware.

You must be in either the schematic or text editor to usethis menu item.This menu item only works in an editor.

You must be in the =SCHEMAX= editor window to usethis menu item.This menu item only works in =SCHEMAX=.

You must have a =SCHEMAX= (.SCH) file loaded to usethis menu item.This menu item only works if a schematic has been loaded.

=SCHEMAX= ERRORS

A fatal internal =SCHEMAX= error has occurredIf this error occurs, please contact Eagleware.

Different names found on input and output of networkIf both the input and the output of a network are named,the names must be exactly the same. Choose one nameand delete the other one.

Invalid port number used (__) in network __.Port numbers must be a single digit between 1 and 9.

384 Error Messages

Models should contain exactly one network. This sche-matic contains __ networks.Each model definition can only contain one model and maynot contain sub-networks.

Multiple port #__’s found in network __There may be multiple networks on a schematic, but theremay be only one of each port # in a network.

Networks contain circular references. Cannot write file.Your schematic has two or more networks that are refer-ring to each other. You must redesign the schematic sothat circular references no longer occur.

No name given for a NET block. Name all NET blockswith the name of the referenced network.The NET block contains an invalid network name.

No name given for a network. This name must be speci-fied in the input.Each network must have a name on either the input oroutput, specified through the input or output dialog boxes.After placing the INP on the circuit, you are automaticallyasked for a name.

Port #__ connected directly to ground in network __Ports cannot be connected directly to ground.

Port #__ is missing in network __.Each network must use port numbers sequentially. Usethe IN and OUT buttons to place them on your schematic.

Substrate names beginning with Default cannot besaved to the library. Rename the substrate and resave it.The subtrate has Default in its name. Default is reservedfor the default substrate in =SCHEMAX=. Although the

Error Messages 385

default substrate can be chosen, no substrate can benamed default.

Too many pins for model __ used in part __.The element used in =SCHEMAX= for a model has toomany pins (terminals).

Undefined substrate __ used in part __You must specify the substrate you want to use in thedialog box for each part. Use the Substrate menu to adda substrate or edit an already existing substrate.

Unnamed NET block found in network __. Name all NETblocks with the name of the referenced network.Name all NET blocks with existing network names.

Warning:Part connected between grounds has no effect.There is a part that has ground on both ends. Note that avoltage source is considered an RF ground.

TOUCHSTONE TRANSLATION ERRORS

Error in Touchstone Validation parameter (TCHVALID).This error should not occur.

Error in Touchstone Parameter Translation (TCHPARM).This error should not occur.

If units other than MM are used, CPL/TLP parts must notuse a variable or a tuned value for length.The indicated part has a variable or tuned length, but thecurrent substrate uses units other than 1.

Warning: In Touchstone, attenuation in CPL/CLINP is notfrequency dependent.Touchstone’s attenuation is constant with frequency, andmay vary from =SuperStar=’s frequency dependent model.

386 Error Messages

Warning: In Touchstone, attenuation parameters are re-quired in CPL/CLINP. Using 1E-9 for AE and AO.The indicated part is missing attenuation parameters.The value shown has been substituted during translation.

Warning: In Touchstone, frequency and attenuation pa-rameters are required in TLE/TLINP. Using 1E-9 for A and1000 for F in part __.Either frequency or attenuation was left out of the indi-cated part. The values shown have been substituted.

Incomplete or missing parameter on line __ of text por-tion of schematic.The line does not have a complete parameter list.

Invalid output types (__).The indicated output selection is not supported.

Missing frequency in FREQ block.The FREQ block is missing a parameter. Check the outputrequest line for missing parameters.

Missing frequency in OPT block.The OPT block is missing a parameter. Check the optimi-zation requests for missing parameters.

Missing parameter in part __.The part is missing a required value for translation.

Missing parameter in substrate __ used in part __.The indicated substrate is missing a required parameterfor translation of the indicated part.

Warning: MST asymmetrical does not have a Touchstoneequivalent in part __. Using symmetrical.Self explanatory.

Error Messages 387

Warning: MVH radius cannot be tuneable in part __.A tuneable radius is not allowed for translation.

Warning: Only one unit type per circuit is allowed.Conflicting units were found on different substrate decla-rations. Units must be consistent throughout the circuitfor translation.

Required parameter (_) was not given in part _ of type _.A parameter was not given which is Touchstone requires.

There is no schematic to translate!The schematic is empty

Touchstone does not support __ in part __.The indicated part is not supported for translation.

Touchstone does not support E12 for optimization.E12 has been selected for optimization, but cannot betranslated.

Touchstone does not support E12 for output.E12 has been requested, but cannot be translated.

Warning: Touchstone does not support full nodal noiseanalysis.Noise figure data was requested, but is not available forcomplete circuit simulation (Available for devices only).

Touchstone does not support IF, GOTO, and LABEL fromthe =SuperStar= EQUATE block.Conditionals were found in the EQUATE block,but are notsupported for translation.

Warning: Touchstone does not support Polar charts(POL), using Smith charts instead.POL in the WINDOW blocks has been translated to SMH.

388 Error Messages

Warning: Touchstone does not support the flatten opera-tor (%).The delay flatten operator is not supported in Touchstone.

Warning: Touchstone does not support Zo.In Touchstone, these elements use the terminating imped-ance of the network as Zo.

Warning: Touchstone does not support thickness.Use care: The resulting simulation may not be accurate.

Touchstone only supports a transformer secondary ofone in part __.The indicated transformer must use a secondary of 1.Divide each side by the secondary number to adjust, if novariables are used.

Warning: __ - Touchstone only supports one frequencyrange per circuit file.More than one frequency range has been specified, butonly the first will be used.

Touchstone only supports one set of terminations per2-port name. Window __ is used more than once withdifferent terminations.The indicated window has been used before with differentterminations. This is not allowed in Touchstone.

Touchstone only supports the TR (turns ratio) trans-former option in part __.The indicated transformer has impedance ratio selected,but must use turns ratio for translation.

Warning: Touchstone parts PRC, PRL, PRLC, SRC, SRL,and SRLC do not support Q in part __.The element has been translated using ideal L’s and C’s.

Error Messages 389

Touchstone requires nodes 3 and 4 of GYR (gyrator) tobe grounded in part __.The indicated nodes must be connected directly to ground.

Touchstone requires the third node of NET parts to begrounded in part __.The third node of the indicated network block must beconnected directly to ground.

Touchstone requires the last node to be grounded inTHR, FOU, and NPO in part __.The indicated node must be connected directly to ground.

Touchstone substrate model for __ requires a heightThe part requires a height, but none was specified.

Touchstone translations don’t support postprocessing.Combined responses are not translatable.

Touchstone uses only specific units. Valid values are:0.001(UM), 0.0254(MIL), 1.0(MM), 10(CM), 25.4(IN), and1000(M). Check the default substrate.One of the substrates contained in the circuit does not useone of the above units.

Touchstone’s BIP and FET models are not compatiblewith =SuperStar=. Use TWO instead.The models used by Touchstone do not coincide with the=SuperStar= transistor models. Use S-Parameter devicesinstead, or edit the translated file and use a Touchstonemodel.

Warning: Touchstone’s TLIN model does not use an at-tenuation model in part __.The indicated part has an attenuation specified, butTouchstone’s model will not include it.

390 Error Messages

__ - Unknown frequency code.The indicated line contains an error.

Unrecognized DSP option __.The indicated paramter is not supported for display, andcannot be translated.

Unrecognized GPH option __.The indicated option is not supported for output selection.

Validation error (__) in part __ of type __.The part cannot be translated accurately to Touchstonedue to the condition shown.

Variables cannot be used in place of frequency in FREQblock.A variable, or non-number has been used where a numbershould have been in the FREQ block.

Variables or tunable elements may not be used within theMUI model in part __.The indicated part contains variables or tunable values,and cannot be translated.

SPICE TRANSLATION ERRORS

Warning: Cannot find subcircuit __ referenced by __ incircuit __.An undefined network name was referenced in the indi-cated circuit.

Equations with operators (such as ‘+’ or ‘-’) can’t beexported to Spice. The first illegal line is __. Edit the textand replace it with a simple assignment such as X=5.The indicated line contains an illegal equation.

Error Messages 391

Error writing file __.The indicated file was not written due to a file error.

Invalid filename, cannot write Spice file.The filename chosen is not valid, and can’t be written to.

Invalid subcircuit reference at nodes __.The indicated nodes are connected to an undefined orunnamed subcircuit.

Warning: OpAmp subckt X$__ is a only a simplifiedapproximation; Crossover frequency is not modeled.The indicated op-amp does not model frequency-depend-ent gain.

Primary Circuit (_) not found. Check Spice Preferences.An undefined network name was given for the primarycircuit translation.

Selected SPICE version(__) does not support __ parts.The SPICE target version does not support the part.

SPICE does not support __ parts.SPICE does not support the indicated parts.

Spice does not support ideal TRF’s. Part __ should bereplaced by an MUI.The indicated part is not an ideal transformer. Instead,use mutually coupled inductors (MUI).

There is no schematic to translate!Export was selected, but there is no schematic loaded.

User defined device __ at nodes __ is missing userparameters.The indicated device is missing parameters.

392 Error Messages

INDEX

!+ button 22- button 2290 Button 22—- button

see Line button

A=A/FILTER= 314ABC (inline ABCD parameters) 177,

183ABCD parameters 334, 337About =SuperStar= 314ABS (absolute value) 74Accuracy 76, 340, 346-348, 350AIRIND1 (Air-core solenoid) 176, 184Algebraic equations

see EQUATE blockAlgorithms 333

Computational classes 337Node Elimination 336

Amplifier 59ARCCOS (inverse cosine) 74ARCCOSH (inv. hyperbolic cosine) 74ARCSIN (inverse sine) 74ARCSINH (inv. hyperbolic sine) 74ARCTAN (inverse tangent) 74ARCTANH (inv. hyperbolic tangent) 74ASCII 48, 52, 204, 232, 274, 302Audio bandpass filter 150AUDIOBPF.CKT/SCH 150Automatic optimization 310

see also Optimization

BBandpass Filter 65Bibliography 361BIP (bipolar transistor) 23, 177, 185BRIDGE-T.CKT/SCH 122

CCAP (capacitor) 23, 173, 187, 300Capacitor parasitics 341Cascade 312CCC (Current-controlled current

source) 177, 188CCV (Current-controlled voltage

source) 177, 189CEN (Coaxial end) 24, 178, 190CGA (coaxial gap) 24, 178, 191Characteristic impedance 315CIR3 (Circulator) 174, 192CIRCUIT block 66, 173, 299-300Circuit file structure 299Circuit Simulator Types 338

see also Simulator TypesCLI (coaxial line) 24, 178, 193CLI4 (coaxial line) 24, 178, 194Close All Windows 312Close Window 312COAX group 24Coaxial models

see Physical modelsComments 70Common emitter 51Common source 51Component reuse 301Component tolerance

see Monte CarloCONVERT program 359Converting .SCH to .CKT 357Copy 303COS (cos) 74COSH (hyperbolic cosine) 74Coupler 148CPL (two coupled lines) 24, 175, 195CPN (n-coupled lines) 24, 175, 196Creating new data files 48Crystal

see XTL (crystal)

CST (coaxial step) 24, 178, 198Curved Line 214Cut 303

DDEF2P 299, 301DELAY 174, 200Deleting an element 14Design centering 95

see also Monte Carlo analysisDevice data 47DEVICE group 23Device models 177, 343-344Diode 238DIPOLE 176, 201DIS (discrete) 35Discrete devices 47Dispersion 346Display Markers 9, 311Drivers 353

Code description 354Example 354-355Source code 354

DSP (tabular display) 30_DTOR 75

Ee 75EDGEFILT.BAS 353Edit menu 303Editing files 307

see also Text editorElement classes 333, 337_EPS0 75=EQUALIZE= 314EQUATE block 65-77, 350

Example 65, 71, 75, 148Expression format 72Functions 74Limits 75Logical operators 73, 76Operators 72Precision 76Reference 70Reserved words 77Tuning 67Viewing Variable Values 68

Error messages 367-392During translation 368

Red error bar 367=SCHEMAX= operation 384=SuperStar= operation 381

Error value 58_ETA0 75Exact models 174, 343Examples 121Execution speed 60, 75, 301, 333,

335, 350Exit 12, 304, 307EXP 74_EXP1 75Exponential line 281Extension 52Extrapolation 204, 232, 274

FFBPAIR.CKT/SCH 152FET (transistor) 23, 177, 202File Menu 305File naming convention 52File record keeping 50=FILTER= 314FIX (truncate) 74FOU (four-port data) 23, 47, 51, 177,

204FREQ (sweep frequency) 75FREQ block 52Frequency domain 338-339Functions 68

see also EQUATE block

GGAIN 174, 205Generate Report

see Monte Carlo analysisGND (ground) button 23GOTO statement 71GPH (graph) 30-31, 33Gradient search

see OptimizationGradient search optimization 310Ground 299Group delay 67, 337GYR (gyrator) 23, 175, 206

HHarmonic Balance 338-340Help 304

394 Index

Help menu 314Highpass filter 13, 122Hybrid mode device 148

IIF ... THEN GOTO statement 71, 76Importing device data 47IND (inductor) 23, 173, 207Inductor parasitics 341Initial step percentage 57INP (input) button 22Input impedance 319INT (greatest integer) 74Interdigital capacitor 217

see also MIDCAPInterpolation 204, 232, 274ISOLATOR 175, 208

KKeyboard commands 10, 20, 303

LLABEL statement 71Lead spacing 341Library 48Line button 22Linear Simulators 47, 338-339LN (logarithm base 2) 74_LN2 75LOG (log graph) 30-31, 33LOG (logarithm base 10) 74Logical operators

see EQUATE blockLOOPOSC.CKT/SCH 144Lowpass filter parasitics 341Lumped Element Approximations 176LUMPED group 23

MM button 22=M/FILTER= 314Markers 9, 311=MATCH= 314Matching network 324Maximize/Restore 312MBN (microstrip bend) 24, 178, 209MCN (microstrip n-coupled lines) 24,

178, 210MCP (microstrip two-coupled lines) 24,

178, 212MCR (microstrip cross) 24, 178, 213MCURVE 178, 214MEN (microstrip end) 24, 178, 215Menu bar 305MGA (microstrip gap) 24, 178, 216MICROSTRIP group 24Microstrip models

see Physical modelsMicrowave filter 353MIDCAP 179, 217Mirror 20MLI (microstrip line) 24, 179, 218Models 340MONOPOLE 176, 219Monte Carlo analysis 85-98, 310

Design centering 95Example 86, 96.MC file 90Normal distribution 92Printing 90Report 95Seed 91Sensitivity analysis 95Setup 90, 311Sigma 90Worst case 85, 92YIELD block 93

MRIND (Rectangular inductor) 179,220

MRS (microstrip radial stub) 24, 179,222

MSPIND (Spiral Inductor) 179, 223MST (microstrip step) 24, 179, 225MTAPER 179, 227MTE (microstrip tee) 24, 179, 228_MU0 75MUI (mutually coupled inductors) 23,

175, 230MVH (microstrip viahole) 24, 179,

231

NNamed Components 300-301NET (reuse network) button 23Network analyzer 315, 334Network parameters 333New File 305

Index 395

Next Window 312Nodal analysis 333, 335Node elimination 336Nodes 299Noise figure 52, 337Non-Ideal elements 341Non-Linear analysis 338NOTEPAD 303NPO (n-port data) 23, 47, 51, 177, 232

OONE (one port) 47OPA (operational amplifier) 23, 177,

234OPAFILTR.CKT/SCH 138Open

All Responses 312Error Messages 313View Variables 68, 313

Open File 7, 306Operators

see EQUATE blockOPT block 57-58, 93Optimization 55

Automatic 11, 56, 310Example 59Gradient 55Marking Elements 57Objective function 56Overview 11Pattern Search 55, 310Physical models 350Smooth Background Operation 310Weights 63

Optimize menu 309OSCBFR96.CKT/SCH 142Oscillator 142, 314OUT (output) button 22Output data files 52Output parameter classes 333

PP button 22Package modes 341Parasitics 340-341, 346Paste 303Pattern search optimization 310

see also OptimizationPFC (parallel resonator) 174, 235

PFL (parallel resonator) 174, 236PHASE 175, 237Physical models 178, 340, 346-347

Coaxial 24, 178, 344Example 164Execution speed 350Indication of need 348Microstrip 24, 164, 178, 345, 347Optimization 350Slabline 24, 179, 345Stripline 25, 179, 345Waveguide 25, 180, 345

PI 75Piezoelectric resonator

see XTL (crystal)PIMATCH.BAS 355PIN (Diode) 176, 238PLC (parallel L-C) 173, 240Plot 307POL (polar chart) 30, 32PRC (parallel R-C) 174, 241PRD (sweep delta) 38PRI (parameter sweep) 37Print Screen 90, 307Print Window 90, 307PRL (parallel R-L) 174, 242PRL (sweep log) 38Production Considerations 85

see also Monte CarloProfessional Version of =SuperStar=

see =SuperStar= ProfessionalProvided device data 47PRX (parallel R-L-C) 174, 243

QQ 300Question marks

see TuningQuick reference, circuit codes 173

RR button 22Radiation 346RCLIN 175, 244RCN (slabline n-coupled) 24, 179,

245RCP (slabline two-coupled) 24, 179,

247Rectangular inductor 220

396 Index

see also MRINDRed error bar 367Redistribute Markers 9, 311Reference 173References 361Reflection coefficient 316RES (resistor) 23, 173, 249RESL 69RFUNIT.CKT/SCH 129RIBBON 175, 250RLBRIDGE.CKT/SCH 154RLC Models 173RLI (slabline) 24, 179, 251RND (random) 74Rotate an element 22Round rod (slabline)

see Physical modelsRound-off error 72_RTOD 75Rules for nodal conections 299Run

=EQUALIZE= 314=FILTER= 314=M/FILTER= 314=MATCH= 314=OSCILLATOR= 314=TLINE= 314

SS-Parameters 47, 204, 232, 274, 306,

315-332, 334, 344Creating 303Definition 317Editing 304Importing 47Introduction 315Matching 324Provided files 48Stability 320Transducer power gain 324Writing 52, 306

Save File 306Save File As 306Save Marker Blocks 9, 311SBN (stripline bend) 25, 179, 252Scattering parameters

see S-ParametersSCH2CKT program 357

=SCHEMAX= Walkthrough 13-25SCN (stripline n-coupled lines) 25,

179, 253SCP (stripline two-coupled lines) 25,

180, 255Screen Dump

see Print Screen and Print WindowSeed 91SEN (stripline end) 25, 180, 256Sensitivity analysis 95, 311Setup Monte Carlo 311

see also Monte Carlo analysisSFC (series resonator) 174, 257SFL (series resonator) 174, 258SGA (stripline gap) 25, 180, 259Shell menu 314SIG (signal ground) button) 23Sigma

see Monte Carlo analysisSimulator Types 338SIN (sine) 74SINH (hyperbolic sine) 74Slabline

see Physical modelsSLABLINE group 24SLC (series L-C) 174, 260, 301SLI (stripline) 25, 180, 261SMH (Smith chart) 30, 33Smith chart 329Smooth Background Operation 310

see also OptimizationSPA (inline S-parameters) 262Sparse matrix 335SPICE 338-340SPIND 176, 263Spiral Inductor 223

see also MSPIND,SPINDSQR (square root) 74SRC (series R-C) 174, 265SRL (series R-L) 174, 266SRX (series R-L-C) 174, 267SSP (stripline step) 25, 180, 268Stability factor 320Statistical analysis

see Monte CarloStatistics Menu 310Status area 57STE (stripline tee) 25, 180, 269

Index 397

Step size 57STRIPLINE group 25Stripline models

see Physical modelsSUB (substrate) 180, 270=SuperStar= Models 340SWD (sweep delta) 35SWL (sweep log) 36SWP (sweep points) 37, 39

TT-LINES group 23TAN (tan) 74TANH (hyperbolic tangent) 74Tapered line 227

see also MTAPERText editor 302

Help 304Keyboard commands 303Leaving 304Status area 304

TFC 176, 272TFR 176, 273Thin film capacitor 272Thin film elements

see TFC, TFRThin film resistor 273THR (three-port data) 23, 47, 51, 177,

274Tile Horizontal 312Tile Vertical 312Time domain 338-340TL_COUPL.CKT/SCH 148TLE (electrical transmission line) 275TLE (transmission line) 23, 175TLE4 (transmission line) 23, 175, 276=TLINE= 314TLP (transmission line) 23, 176, 277TLP4 (transmission line) 23, 176, 278TLRLDC 176, 279TLRLGC 176, 280TLX 176, 281Toggle background color 312Toggle Grid Style 311Tolerance

see Monte CarloTORIND 177, 282Transformer 148

Transistors 47, 344Translate, loading values from editor

11Transmission coefficient 316Transmission Lines 175

Electrical models 346-347, 349see also Physical models

Transmission systems 329Traveling waves

see S-ParametersTRF (transformer) 23, 175, 283TRFCT (Tapped TRF) 175TRFRUTH (Ruthroff Transformer)

285Tunable filter 136Tuning

Circuit 9Equations 67Marking elements 57, 88Menu 307Step size 10

TVROBPF.CKT/SCH 158TWO (two-port data) 23, 47, 177, 286Two-Port analysis 333-335TXT (text) button 20, 23

UUnits 46, 173, 302Update solid traces 11Utilities Menu 9, 311

V_VAIR 75Variable Names 72VCC (voltage controlled current

source) 23, 177, 287VCV (voltage controlled voltage

source) 178, 288Version 3.4 and older 359-360

CONVERT program 359Running old files 359

View Variables Window 68Voltage traveling waves

see S-ParametersVolterra-Series analysis 340VSWR 319

398 Index

WWAD (Waveguide adapter) 25, 180,

289WAVEGUIDE group 25Waveguide models

see Physical modelsWeights

see OptimizationWILKNSON.CKT/SCH 126Window menu 312Window specification 35WIRE 176, 290Wires 175WLI (rectangular waveguide) 25, 180,

291Worst Case

see Monte CarloWrite S-Data 306

see also S-ParametersWriting text on the circuit 23

XXTL (crystal) 23, 180, 292

YY matrix 335Y-Parameters 49, 315, 334YIELD block 93

see also Monte Carlo analysisYield optimization

see Monte Carlo analysis

ZZ-Parameters 335Zooming in/out 22

Index 399

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