senior project 2008

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Senior Project 2008. Ultra Wideband Amplifier Sarah Kief Saif Anwar Advisor: Dr. Shastry Bradley University Electrical Engineering. Outline. UWB overview Project Description Design procedures Lumped element Design M-derive Design Layout Microstrip Design Coplanar Wave Guide Design - PowerPoint PPT Presentation


  • SENIOR PROJECT 2008Ultra Wideband AmplifierSarah KiefSaif Anwar

    Advisor: Dr. Shastry

    Bradley UniversityElectrical Engineering

  • OutlineUWB overviewProject DescriptionDesign proceduresLumped element DesignM-derive Design LayoutMicrostrip DesignCoplanar Wave Guide DesignFinal LayoutFuture work

  • Applications

  • Block Diagram

  • Ultra Wideband OverviewUWB definitionSpectrum, 3.1 10.6 GHzLarge bandwidth, low power, short distancesUses Gaussian Pulses.

  • Frequency Spectrum

  • UWB HistoryHistoryFirst used in 1901Gugleilmo Marconi transmitted Morse code using spark-gap radio transmitters1960s to 1980s restricted to government use1998 FCC legalized for commercial use

  • Previous WorkSenior Project 2007 done by Jarred Cook and Nathan Gove.Goal was to create a scaled down UWB transceiver. Research done by other members of the scientific community.

  • Previous Work

    ReferenceGain (dB)NF (dB)BW (GHz)PD (mW)TopologyTechnology[1] m CMOS[2]106.43.1-10.65.4Distributed0.35 m SiGe BiCMOS[3]95.33.1-10.622Distributed0.18 m CMOS[4] 206.51.6-12.140Low Power Distributed0.35 m SiGe BiCMOS[5]7.34.3-6.10-2253Distributed0.18 m CMOS[6]10.63.4-5.30-1452Distributed0.18 m CMOS[7]661-2768.1Distributed0.18 m CMOS

  • Project DescriptionFunctional DescriptionTopology: Distributed Amplifier (DA)Low Noise Amplifier (LNA) implemented with a Gas FETs-NE4210S01, Pseudomorphic Hetero-Junction FETSpecificationsGain: 16 dBNoise Figure: 2.5 dBRequirementsFrequency RangeExternal Interferences

  • External Interferences

    StandardFrequency RangeReferenceIEEE 802.11a5 GHz[8]IEEE 802.11i2.4GHz and 5GHz[8]IEEE 802.16WiMAX2GHz 11 GHz[9]

  • DC-IV Curves

  • Bias SelectionDC-IV curves and bias point selection.

  • Cin and Cout Calculation

  • Lumped Component Schematic

  • M-Derived Design

  • Microstrip Line DesignTranslated lumped element components into respective lengths and widths in the MSTRIP programCapacitors Zo=30 ohmsInductor Zo=90 ohmsBuilt layout in ADS and simulated

  • Microstrip Layout

  • SimulationsAmplifier GainPhase Linearity

  • Stability Factor

  • Coplanar Wave Guide DesignTest TransistorsChose RT/Duriod 6002 boardThickness : .508 mmDielectric Constant : 2.94 1 oz copper platingHigh mechanical strength Designed dimensions Line calc in ADSWidth of center conductor = 1.24 mmAir Gap = .63 mmLength of center conductor = 10 mm

  • Full Coplanar Wave Guide

  • Half Coplanar Wave Guide Layout

  • ADS Schematic of Coplanar Waveguide

  • Layout Simulation

  • De-Embedding In AdSEquation 1: Tm = Tmeasured = stot(s)Equation 2: Tf = Tm/(((stot(simulations_half_cplanarwg(s))))^2Equation 3: St = ttos((Tf)

  • DC-IV Curves of Transistor

  • Final Amplifier Layout

  • SimulationsAmplifier GainPhase Linearity of Amplifier

  • Stability Factork = stability check, k 1 (unconditionally stable)b = stability measurement, b has to always be positive

  • Noise Figurenf(2) is the noise figure of the ultra wideband amplifier over the spectrum.NF is the mean value, 2.06 dB

  • Future Work Manufacture new full coplanar waveguidesMeasure S-parametersDo de-embeddingRun simulation of amplifier using s-parameter from de-embeddingRe-optimizeManufacture the amplifier

  • Questions?

    Welcome screenWelcome, fellow students and faculty members to this years senior presentation of the Ultra Wideband Amplifier. My name is Saif Anwar and this is my partner sarah kief. Today we will discuss the topic of the ultra wideband system and where our ultra wideband amplifier fits into the grand scheme of things. (click)

    *In this project we will first discuss the Ultra Wideband system and what it is, then go through the project description, outline and discuss the design procedures, talk about the challenges faced and results we have gotten thus far, and then future work.(click)*What is the ultra wideband system?This picture represents the perfect application of an entire UWB system. If you look at in the middle of the picture, there is a big black box called the home controller device. Now imagine using this device to control anything from your lighting systems to motion sensors, position sensors, transmitting high definition video images wireless from one room to another. This technology will literally eliminate almost all the wires at home. But to do this need a good receiver and a transmitter device.(click)*Here is a block diagram representing the ultra wideband system. (discuss wats on the picture). The low noise amplifier is where we come in. This is the part that my partner and I have spent the last year working on and it has proved to be a very challenging project. Many facets of this project were completely new to us, so a lot of research had to be done on multiple topics including software used to implement the design this will be later discussed by my partner. Now that we have talked about how the system works let us define what the ultra wideband system is.(click)

    **Ultra wideband system stands for transmission of large bandwidth using low power over short distances. The frequency range for this system is 3.1 GHz to 10.6 GHz. It uses Gaussian pulses to transmit data back and forth from the receiver and transmitting antennas. (click)Here we can see the am and fm frequency spectrum to help us visualize where the uwb spectrum lies among all the other frequencies. (talk a little abt the frequency spectrum) (click)*Getting all this started was done by a person named Guiamo Marconi, it was first used in the year 1901, when he transmitted morse code using a spark-gap radio transmitters. At that point this discovery intrigued great interest for military and civilian usage. From 1960s to 1980s it was restricted for government use only and then from 1998 FCC legalized it for commercial use. Now I will hand it off to my partner to discuss the later parts of this project.(click)*Last year the goal of the project was to implement an entire UWB transceiver as made.This provided some basic background knowledge of the basis of UWB systems. The learning curve of this project was very large. So we started by researching different work done by other members of the scientific community.

    *We Researched mainly DA topologies to see their noise figures , gains and power. Since we had no prior knowledge with UWB systems we chose to pick specifications based on previous research as a starting point. We chose an average gain specification and noise figure as our starting specification. Since, we did not know exactly what results we would get for our first design of our amplifier this was a good place to start.

    *A DA was used because it is especially designed for wide band applications and gives a low noise figure design. These are both very important. Since our amplifier is on the we are on a receiver side of the UWB transceiver we want to add as little noise as possible to the system so that it does not get amplified by other amplifiers in the receiver.

    *These will be encountered in the future UWB implementation in industry rather than in our actual project. This is important to understand that UWB overlaps in frequencies and be ware of the problems that can encounter outside lab environments.

    *The first step in design is to obtain the DC IV curves of the transistor. We first built this model in Advanced Design System. This was our first real encounter with ADS so there was a large learning curve involved to learn the software. This schematic shows a biasing scheme using a nonlinear model of our transistor provided by the manufacturer. This was simulated to produce the DC IV curves on the next slide.

    *These curves were used to pick the biasing used for the transistor in the amplifier design. By choosing different biasing points it allows the transistor to be biased for certain characteristics. We biased the transistor for the lowest noise figure. So the VDS was 2 volts, vgs was -.45 at 10mA

    *The next step in design is to simulation is to use ADS to simulate the cin and out value of the transistor. These will be used later to determine if padding capacitors are needed in the DA schematic design.

    *The lumped element design is the first step in amplifier design. Basic design equations were used to determine the L and C values used between the cascaded transistors. The XXXXX circle shows the biasing circuitry which will be used to bias the transistor with the current and voltage chosen in previous slides. The matching networks were also design using basic design equations. The matching network matches the input and output ports of the amplifier. The closer the match the less losses occur. The next design step is to make use of the padding capacitors.

    *The padding capacitors are decided if necessary by using a design equation involving the cin and cout values previously measured. If the result of this equation is a negative capacitance a padding capacitor is not needed. After the padding capacitor is found , it is time to translate it into inductance. This is called the m-derive method which is done by design equations. This translation puts the inductance on the drain and gate sides of the transistor which gives us a lumped element component there to translate into microstrip line. This is convenient for later use in the microstrip layout design.

    **The lumped element components were all translated into microstrip lines using standard design equations. Each component gets a certain length and width depending on its inductance or capacitance. The microstrip line