Aerospace and Defense Symposium 2010Agilent Seminar
Seminario Agilent
Dispositivi non lineari:
una breve introduzione dei Parametri X
e del Nonlinear Vector Network Analyzer
Aerospace and Defense Symposium 2010Agilent Seminar
Evolution of the Tools & Measurements
TOOLS:
NA
SA/SS/NFA
Power meter
Oscilloscope
DC Parametric Analyzer
MEASUREMENTS:
Gain compression, IP3, IMD
PAE, ACPR, AM-PM, BER
Constellation Diagram, EVM
GD, NF, Spectral Regrowth
ACLR, Hot “S22”
S-Parameters
TOOLS:
Vector Network
Analyzer
MEASUREMENTS:
Gain
Input match
Output match
Isolation
Transconductance
Input capacitance
S-Parameters +
Figures of Merit
TOOLS:
SS & Oscilloscope
Grease pens and
Polaroid cameras
Slotted line
Power meter
MEASUREMENTS:
Bode plots
Gain
SWR
Scalar network analyzers
Y & Z parameters
PatchworkNVNA +
X-Parameters
Aerospace and Defense Symposium 2010Agilent Seminar
Agenda
• Steps and Architectures in Network Analysis
• Nonlinear VNA and X-Parameter
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Aerospace and Defense Symposium 2010Agilent Seminar
Network Analysis Step1:
S Parameter (1965)Linear or nonlinear networks operating with
signals sufficiently small to cause the
networks to respond in a linear manner, can
be completely characterized by parameters
measured at the network terminals without
regard to the contents of the networks.
- Relatively easy to obtain at high frequencies (measure voltage
traveling waves with a vector network analyzer don't need shorts/opens
which can cause active devices to oscillate or self-destruct);
- Relate to familiar measurements (gain, loss, reflection coefficient ...);
- Can cascade S-parameters of multiple devices to predict system
performance;
- Can compute H, Y, or Z parameters from S-parameters if desired;
- Can easily import and use S-parameter files in our electronic-
simulation tools.
• K. Kurokawa, ‘Power Waves and the Scattering Matrix,IEEE Transactions on Microwave Theory and Techniques, Vol. MTT-13, No. 2, March, 1965.
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Aerospace and Defense Symposium 2010Agilent Seminar
Modern VNA Block DiagramRF jumpers
Receivers
Mechanical switch
C
R3
Test port 1
R1
Test port 4
R4
A D
rear panel
Pulse generators
1
2
3
4
Source 1
OUT 1 OUT 2
Pulse
modulator
Source 2
OUT 1 OUT 2
Pulse
modulator
Test port 2
R2
B
Noise receivers
10 MHz -
3 GHz
3 -
26.5
GHz
To receivers
LO
+28V (for noise source)
Test port 3
Signal
combiner+
-
Impedance tuner for noise
figure measurements
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Aerospace and Defense Symposium 2010Agilent Seminar
Network Analysis Step2:
X Parameter (2007)Agilent Technologies has
developed X-parameters.
X-parameters represent and
analyze the nonlinear behavior of
RF components in a much more
robust and complete manner. As
an extension of S-parameters
under large-signal operating
conditions, they are driven into
saturation (the real-world
operating environment) and then
measured under these
conditions.
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Aerospace and Defense Symposium 2010Agilent Seminar
Agenda
• Steps and Architecture in Network Analysis
• Nonlinear VNA and X-Parameter
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Aerospace and Defense Symposium 2010Agilent Seminar
Designing a Power Amplifier (1)
The designer wants to drive the amplifier
into the nonlinear region (large signal)
to get the maximum output power as well as
to extract the maximum efficiency
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Aerospace and Defense Symposium 2010Agilent Seminar
Designing a Power Amplifier (2)
Under large-signal conditions there are nonlinear effects:
- distort waveforms (time domain),
- harmonics, inter-modulations… (frequency domain).
S-parameters can only analyze and model the linear behavior.
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Aerospace and Defense Symposium 2010Agilent Seminar
Current Techniques for a Non-linear Device
Linear parameters
S=parameters
Data sheets for amplifiers often have both linear and non-linear information
Non-linear parameters
IMD
Pout vs Pin
P1dB
PAE
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Aerospace and Defense Symposium 2010Agilent Seminar
A [new]-parameter file like a 3-D CAD file
[new] Parameter file3-D file
The “library” contains all the necessary information
[new]-parameter S-parameter
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Aerospace and Defense Symposium 2010Agilent Seminar
X-parameters come from the
Poly-Harmonic Distortion (PHD) Framework
Port Index Harmonic (or carrier) Index
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Aerospace and Defense Symposium 2010Agilent Seminar
Harmonic Superposition Principle
• In general, we are working under large-signal, nonlinear operating conditions.The superposition principle (parameters of individual components are sufficient to determine the parameters of any combination of those components) is not valid.
• In many practical cases (power amplifiers stimulated with a narrowband input signal) there is only one dominant large-signal input componentpresent (A11).All other input components (the harmonic frequency components) are relatively small. In that case, we will be able to use the superposition principle for the relatively small input components.
• This is called the harmonic superposition principle.
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Aerospace and Defense Symposium 2010Agilent Seminar
Harmonic Superposition Principle• (to keep the graph simple) Only consider the presence of the A1m and
B2n components (neglect the presence of the A2m and B1n).
• Case A11 <> 0. A1m and B2n are indicated by black arrows. Note harmonic components for the B2n components.
• Leave the A11 the same and add a small A12 component (second harmonic at the input). This will result in a deviation of the output spectrum B2The same holds for a third harmonicand a fourth harmonic.
• The harmonic superposition principle holds when the overall deviation of the output spectrum B2 is the superposition of all individual deviations
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Aerospace and Defense Symposium 2010Agilent Seminar
The [new] X-parameter
Classic S-parameters: only linear behavior and ignore nonlinear
behavior (harmonic, intermodulation, higher order mixing effects).
X-parameters capture linear behavior and linearize
nonlinear behavior about a large signal operating point (LSOP).
NVNA measures X-parameters stimulating the DUT
with a single large tone at port 1 and, in the same time,
injecting additional small tones at both ports 1 and 2
at all harmonics of interest. At least two phase-offset small tones must be injected at each port/frequency of interest in
order to extract the corresponding X-parameters.
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Aerospace and Defense Symposium 2010Agilent Seminar
Test port 3
C
R3
Test port 1
R1
Source
1
OUT 1OUT 2
Source 2 (standard)
OUT 1 OUT 2
Test port 4
R4
Test port 2
R2
35 dB
65 dB
35 dB
65 dB 65 dB 35
dB
65 dB
Rear panel
A
35 dB
D B
SW1 SW3 SW4 SW2
J11 J10 J9 J8 J7 J4 J3 J2 J1
Calibration phase reference
Measurement phase reference
Injecting a large tone at port 1
To port 1 or 3 for calibration
10 MHz
Internal
Reference
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Aerospace and Defense Symposium 2010Agilent Seminar
Test port 3
C
R3
Test port 1
R1
Source 1
OUT 1OUT 2
Source 2 (standard)
OUT 1 OUT 2
Test port 4
R4
Test port 2
R2
35 dB
65 dB
35 dB
65 dB 65 dB 35
dB
65 dB
Rear panel
A
35 dB
D B
SW1 SW3 SW4 SW2
J11 J10 J9 J8 J7 J4 J3 J2 J1
To port 1 or 3
Calibration
Phase
Reference
Ext Source in
Measurement
Phase
Reference
Injecting a drive and probe tone at port 1
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Aerospace and Defense Symposium 2010Agilent Seminar
Test port 3
C
R3
Test port 1
R1
Source 1
OUT 1OUT 2
Source 2 (standard)
OUT 1 OUT 2
Test port 4
R4
Test port 2
R2
35 dB
65 dB
35 dB
65 dB 65 dB 35
dB
65 dB
Rear panel
A
35 dB
D B
SW1 SW3 SW4 SW2
J11 J10 J9 J8 J7 J4 J3 J2 J1
To port 1 or 3
Calibration
Phase
Reference
Ext Source in
Measurement
Phase
Reference
Injecting a drive tone at port 1 and probe tone at port 2
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Aerospace and Defense Symposium 2010Agilent Seminar
DC f0 2f0 3f0 4f0 5f0-f0-2f0-3f0
21
aj2aj2*
Measuring B2,3 which is the
Port2 output value at 3rd harmonic (3f0).X(F)
2,3 … + X(S)23,gh … + X(T)
23,gh …
Aerospace and Defense Symposium 2010Agilent Seminar
Understanding X-parameter display
X-parameters: XFp, XSpq and XTpq
Both the p and q terms are described by a Port and Harmonic combination.
For example: XS21,13
Parameters for each possible (port, harmonic) selection of p For example: for p=(2,1) , and assuming 3 harmonics of interest:
XF21
(XS21,11),(XT21,11)
(XS21,12), (XT21,12)
(XS21,13), (XT21,13)
(XS21,21), (XT21,21)
(XS21,22), (XT21,22)
(XS21,23), (XT21,23)
For a 2-port device, with 3 harmonics of interest at each port:
- there are 6 possible (port, harm) combinations for p.
- each combination yields 13 parameters,
Total of 6*13
78 X-param
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Aerospace and Defense Symposium 2010Agilent Seminar
X-parameters reduce to S-parameters
11
( )
21 11 21| | 0
[ ( )] F
A
X A s
11
( )
21,21 11| | 0
( ) 0T
AX A
-60-25 -20 -15 -10 -5 0 5 10
|A11| (dBm)
-40
40
20
0
-20
dB
( )
21,21
SX
( )
21,21
TX
( )
21 11/ | |FX A
Reduces to (linear)
S-parameters in the
appropriate limit
11
( )
21,21 11 22| | 0
( )S
AX A s
11| |A
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[X]p,f,Vg,Vd,z3
[X]p,f,Vg,V,z2
[X]p,f,Vg,Vd3
[X]p,f,Vg,Vd2
[X]p,f,Vg3[X]p,f3
[X]p,f2
[X]p3
[X]p2
X-parameters is actually a large data library
-- X-param is measured with many variables --
Various
Power
X-param one bookshelf
one library
Measurement takes from tens of
minutes to a several hours depending
on the size of the “library”
[X]p1 [X]p,f1
[X]p,f,Vg2
[X]p,f,Vg,Vd1
[X]p,f,Vg,Vd,z
one page one chapter
[X]p,f,Vg1
one book
one series
of books
[X]p,f,Vg,Vd,z1
Various
Frequencies
Various
gate voltages
Various
drain voltages
one X-param file
Various
load Z
=
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Aerospace and Defense Symposium 2010Agilent Seminar
Calibration
Three step
calibration process:
1) SOLT or TRL style calibration
2) Absolute receiver calibration using a power meter/sensor
3) Receiver phase calibration using Agilent’s new comb generator.
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Aerospace and Defense Symposium 2010Agilent Seminar
Amplitude Calibration
Vector Calibration
Phase Calibration
Phase Reference
X-Parameter extraction/multi-tone source
Standard PNA-X Network Analyzer
NVNA System Configuration
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Aerospace and Defense Symposium 2010Agilent Seminar
1. Nonlinear Component Characterization
* Absolute amplitude and cross frequency relative phase of measured spectra traceable to standards lab
* Data displayed in frequency, time and power domains:- ‘a’ and ‘b’ waves versus sweep domain- V and I versus sweep domain
- V versus I, I versus V
Frequency Domain
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Aerospace and Defense Symposium 2010Agilent Seminar
1. Nonlinear Component Characterization
* Absolute amplitude and cross frequency relative phase of measured spectra traceable to standards lab
* Data displayed in frequency, time and power domains:- ‘a’ and ‘b’ waves versus sweep domain- V and I versus sweep domain
- V versus I, I versus V
Time Domain
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Aerospace and Defense Symposium 2010Agilent Seminar
1. Nonlinear Component Characterization
* Absolute amplitude and cross frequency relative phase of measured spectra traceable to standards lab
* Data displayed in frequency, time andpower domains:- ‘a’ and ‘b’ waves versus sweep domain- V and I versus sweep domain
- V versus I, I versus V
Power Domain
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Aerospace and Defense Symposium 2010Agilent Seminar
1. Nonlinear Component Characterization
* Absolute amplitude and cross frequency relative phase of measured spectra traceable to standards lab
* Data displayed in frequency, time and power domains:- ‘a’ and ‘b’ waves versus sweep domain- V and I versus sweep domain
- V versus I, I versus V
Customize Domain: V/I
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Aerospace and Defense Symposium 2010Agilent Seminar
Three-port X-parameter
Two-tone X-parameter
Pulse envelope domain
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Aerospace and Defense Symposium 2010Agilent Seminar
Nonlinear pulse envelope domain
Configuration, Cal and Meas (Waves and Harmonics): menu Utility > Measurement Domain… > Envelope Domain
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Aerospace and Defense Symposium 2010Agilent Seminar
Don’t you have this problem? device model model takes time and is not accurate
My simulation gave
me a great answer
but the reality is…
I want to start
my design now!
-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0-2.5 2.5
-70
-60
-50
-40
-30
-20
-10
-80
0
freq, MHz
Spectr
um
_out
Transmitted Spectrum
measured
ACPR-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0-2.5 2.5
-100
-80
-60
-40
-20
-120
0
freq, MHz
Sp
ectr
um
_o
ut
Transmitted Spectrum
simulated
ACPR
Modeling: I need a
couple of months
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Aerospace and Defense Symposium 2010Agilent Seminar
X-parameter enables 3 activities to run in parallel
process dev. amplifier desing module desing
before
after
amp designers can start design
without waiting for the model
modeling
process dev.
amplifier design
module design
[X]
[X]
[X]Sim Meas
module designers can start design
with the simulated X-param then with
the measured X-param
Meas
New technologies like GaN
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Aerospace and Defense Symposium 2010Agilent Seminar
Component Char.NVNA
Component Char. ADS
____ -20dBm Input
____ 0dBm input
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Aerospace and Defense Symposium 2010Agilent Seminar
ADSS-parameter vs X-parameter
S-parameter
X-parameter
S-par not valid
____ -20dBm Input
____ 0dBm input
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Aerospace and Defense Symposium 2010Agilent Seminar
ADSS-parameter vs X-parameter
____ -20dBm Input
____ 0dBm input
S-par not valid
S-par
X-par
Transmission Reflection Output Voltage
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Aerospace and Defense Symposium 2010Agilent Seminar
X-Parameter Example on GaN amplifier
• 32 Watt 1.2 GHz GaN (Gallium Nitride) Amplifier,
- PAE (Pout-Pin)/(Vdc*Idc) on datasheet: 55%
1. Measured with PNA-X/NVNA this amplifier and obtained X-parameters.
2.Loaded the measured X-parameters into ADS
3.Performed simulation in ADS:
- ADS predicted an PAE of 75%,
by using optimum output impedance matching circuitry on 1s, 2nd and 3rd harmonic.
4.Realized PCB for this amplifier,
following the ADS suggestion for optimization
5.Measured the PCB (with amplifier mounted on it) with PNA-X/NVNA
- Actual measured PAE was 75%
- Matches ADS prediction
- By using this X-par approach we could achieve 20% better PAE.
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Aerospace and Defense Symposium 2010Agilent Seminar
NVNA X-parameter System – Power budget (120W)
Application Note 1408-19: High Power Amplifier Measurements using Agilent’s Nonlinear Vector Network Analyzer
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Aerospace and Defense Symposium 2010Agilent Seminar
Agilent is using X-parameters
for the internal design and
also selling ICs to the external
customers with X-parameter
files.
USACanadaUKGermanyFranceNetherlnandSwedenTurkeyPolandRomaniaJapanTaiwanChinaKorea
Component manufacturers start to make
X-Parameters available to their customers
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