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Load Pull with X-Parameters

Load Pull with X-ParametersA New Paradigm for Modeling and Design

Gary Simpson, CTOMaury Microwave

March 2009

For a more detailed version of this presentation, go to www.maurymw.com/presentations

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Load Pull with X-Parameters

Outline• Overview – Motivation and Solution

– A New Paradigm for Modeling and Design• Overview of X-Parameters• Traditional Large Signal Model vs X-Parameter Model• System Setup and Operation• Results• Quick Demo• Summary

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Load Pull with X-Parameters

Motivation• PA Design is Becoming More Complex

– Multi-Stage, Doherty, etc– More than Just Matching One Device

• Large Signal Models are Needed– Accurate– Fast Turn-Around

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Load Pull with X-Parameters

Prior ArtSeparate Disciplines

• Load Pull– Determine Match for a Single Device– Verify Large Signal Models

• X-Parameters at 50 Ohms– Good to simulate system with 50 Ohm blocks– But Power Devices are far from 50 Ohms– Measurement was not Easy

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Load Pull with X-Parameters

Solution:Load Pull withX-Parameters

Instant Large Signal Model

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Load Pull with X-Parameters

Instant Large-Signal Model

• Maury Load Pull• Agilent NVNA• SW in PNA-X• Run Sweep Plan• Save X-Param File• Simulate in ADS

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Load Pull with X-Parameters

Instant Large Signal Model

vsrc

Vs_low

vload

Vs_high

WJ_FP2189_PHDWJ_FP2189_PHD_1fundamental_1=_freq1

DC_BlockDC_Block2

DC_FeedDC_Feed1

P_1TonePORT1

Freq=RFfreqP=dbmtow(Pavs)Z=Z_sNum=1

I_ProbeIsrc

V_DCSRC1Vdc=8 V

I_ProbeIs_low

I_ProbeIload

S1P_EqnS1S[1,1]=LoadTunerZ[1]=Z0

DC_BlockDC_Block1

DC_FeedDC_Feed2

V_DCSRC2Vdc=-1 V

I_ProbeIs_high

X-Parameter Component

Industry Breakthrough

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Load Pull with X-Parameters

Load Pull with LSNATime Domain

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Load Pull with X-Parameters

NVNA• “Nonlinear Vector Network Analyzer”• Superset of LSNA• 3-Step Calibration

– Vector Cal – Similar to standard VNA Cal– Power Cal – Use a power meter– Phase Cal – Use a comb generator as a Harmonic Phase

Reference

• Measures Time-Domain and X-Parameters– X-Parameters are Unique to Agilent NVNA

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Load Pull with X-Parameters

linear : S-params

X-params are to non-linear devices like S-params to linear devices.

InOut

non-linear : X-params

In

Out XInIn

Out

OutX

S

In

InIn

Group/Presentation TitleAgilent Restricted

X-Parameter Overview

InS

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Load Pull with X-Parameters

S-ParametersVNA measures amplitudes and phases of Linear signals.

Group/Presentation TitleAgilent Restricted

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Load Pull with X-Parameters

X-ParametersNVNA measures amplitudes and phasesof harmonic distortion signals.

Phases of distortions can bemeasured.

Group/Presentation TitleAgilent Restricted

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Load Pull with X-Parameters

X-Parameter Summary• Non-Linear Generalization of S-Parameters

– S-Parameters are special case where distortion = 0• Frequency Grid Includes:

– All Harmonics– All Intermods– Baseband

• Parameters at Each Freq• Parameters Between Each Freq Combination• Data covers one Large Signal Operating Point

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Load Pull with X-Parameters

Traditional Large-Signal Model• Use Small Signal and DC measurements

– Fit Model Parameters to Data– Time-Consuming– Accuracy Limited in Some Regions of Operation– Technology Dependent– Model is Extrapolated to Large Signal

• Load Pull is Accuracy Reference– Load Pull is Measured at Actual Large Signal

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Load Pull with X-Parameters

X-Parameter Large Signal Model

• Based on Large Signal Measurements of X-Parameter Data

• Includes all Parasitics up to Reference Plane• Technology Independent• Hides Design Details of Device• Load Dependent Data for PA Design

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Load Pull with X-Parameters

X-Parameter Large Signal ModelOver Entire Smith Chart

• In the Past, the X-Parameter model was only used at or near 50 Ohms

• New: Load-Dependent X-Parameters– Co-Developed by Maury and Agilent

• New Paradigm for Modeling and Design

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Load Pull with X-Parameters

X-Parameter Large Signal ModelOver Entire Smith Chart

• Create Instantly from Load Pull Data• Very Accurate

– Based on Large Signal Load Pull Measurement• Region of Validity

– Sweep Plan Range Selected by User– Sweep Gamma, Power, Bias, Freq, Etc.

• Simulate Complex PA Circuits

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Load Pull with X-Parameters

What is Load Pull?Measurement vs. Impedance

TUNERTUNER

Γsource ΓLoad

Stimulus and

Measurement

DUT

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Load Pull with X-Parameters

Load Pull + X-Parameter Setup

PNA-XNVNA + Maury Software

Maury

Tuner

Maury

TunerDUT

Bias

System

Exclusiveto Maury

And Agilent

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Load Pull with X-Parameters

Load Pull to Circuit SimulationSequence

1. Calibrate System, including Tuners2. Calibrate NVNA at DUT Plane3. Connect the DUT and Measure Sweep Plan

• Sweep Gamma, Power, Bias, Freq, Etc.4. Drag and Drop X-Param File into ADS5. Simulate Circuit

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Load Pull with X-Parameters

System Operation - Measurement

•NVNA controlled by Maury ATS software.•X-Params option in parameter selection dialog•Fully automated measurement

December 11, 2008Page 21

NVNA + Load PullInstant Large Signal Model

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Load Pull with X-Parameters

System Operation - Measurement• Sweep Plan• Up to 7 Variables• Fully Automated

Measurement

• Measure over Full Range of Device Operation

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Load Pull with X-Parameters

System Operation - SimulationCopy file into ADS project

X-Parameter Design Kit does the rest!

December 11, 2008Page 23

NVNA + Load PullInstant Large Signal Model

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Load Pull with X-Parameters

Instant Large Signal Model

vsrc

Vs_low

vload

Vs_high

WJ_FP2189_PHDWJ_FP2189_PHD_1fundamental_1=_freq1

DC_BlockDC_Block2

DC_FeedDC_Feed1

P_1TonePORT1

Freq=RFfreqP=dbmtow(Pavs)Z=Z_sNum=1

I_ProbeIsrc

V_DCSRC1Vdc=8 V

I_ProbeIs_low

I_ProbeIload

S1P_EqnS1S[1,1]=LoadTunerZ[1]=Z0

DC_BlockDC_Block1

DC_FeedDC_Feed2

V_DCSRC2Vdc=-1 V

I_ProbeIs_high

X-Parameter Component

Industry Breakthrough

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Load Pull with X-Parameters

Results – Packaged FET Extremely Accurate Agreement

Pout PAE

Blue – Simulated, Red - Measured

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Load Pull with X-Parameters

Results – Packaged FET

0.2 0.4 0.6 0.80.0 1.0

0

5

10

15

-5

20

0.10

0.15

0.20

0.25

0.05

0.30

time, nsec

Me

asu

red

Cu

rren

tMe

asu

red

Vo

ltag

eS

imu

late

dV

olta

ge S

imu

late

dC

urre

nt

Measured and Simulated Voltage and Current Waveforms

0.2 0.4 0.6 0.80.0 1.0

0

5

10

15

-5

20

0.15

0.20

0.25

0.30

0.35

0.10

0.40

time, nsec

MeasuredC

urrentMea

sure

dVol

tage

Sim

ulat

edV

olta

ge

Sim

ulatedCurrent

Measured and Simulated Voltage and Current Waveforms

0.2 0.4 0.6 0.80.0 1.0

4

6

8

10

12

14

2

16

0.1

0.2

0.3

0.4

0.0

0.5

time, nsec

Me

asu

red

Cu

rren

tMe

asu

red

Vo

ltag

eS

imu

late

dV

olta

ge S

imu

late

dC

urre

nt

Measured and Simulated Voltage and Current Waveforms

December 11, 2008Page 26

NVNA + Load PullInstant Large Signal Model

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Load Pull with X-Parameters

Measured vs. SimulatedExtremely Accurate

VoltageCurrent

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Load Pull with X-Parameters

( ) ( )

PAE and Pout vs. Harmonic Loads

0.1% contour step for PAE,0.01dBm contour step for delivered power

PAE (red) and Pout (blue)Second Harmonic Load Third Harmonic Load

December 11, 2008Page 28

NVNA + Load PullInstant Large Signal Model

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Load Pull with X-Parameters

Demo• Quick ADS Demonstration• Drag and Dropping X-Parameter File into

Schematic• Simulate, See Results

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Load Pull with X-Parameters

Summary

• X-Parameters = Non-Linear Data• Instant Large Signal Model• Load Pull + NVNA + ADS

– Load Pull Produces X-Parameter File– Drag and Drop as Large Signal Model

• Very Effective for Complex PA Design

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Load Pull with X-Parameters

Summary

Load Pull with X-Parameters:

• A Fast and Accurate Approach to Large-Signal Modeling and Simulation

• New Paradigm for Modeling and Design– Industry Breakthrough

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Load Pull with X-Parameters

Complex PADesign Solution:Load Pull withX-Parameters

Instant Large Signal Model

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Load Pull with X-Parameters

References[1] J. Verspecht and D. E. Root, “Poly-Harmonic Distortion Modeling,” in IEEE Microwave

Theory and Techniques Microwave Magazine, June, 2006.[2] J. Verspecht, D. Gunyan, J. Horn, J. Xu, A. Cognata, and D.E. Root, “Multi-tone, Multi-

Port, and Dynamic Memory Enhancements to PHD Nonlinear Behavioral Models from Large-Signal Measurements and Simulations,” 2007 IEEE MTT-S Int. Microwave Symp. Dig., Honolulu, HI, USA, June 2007.

[3] J. Horn, D. Gunyan , L. Betts, C. Gillease, J. Verspecht, and D. E. Root, “Measurement-Based Large-Signal Simulation of Active Components from Automated Nonlinear Vector Network Analyzer Data via X-Parameters,” in 2008 IEEE COMCAS Conference, Tel Aviv, Israel, March, 2008

[4] D. E. Root, J. Verspecht, D. Sharrit, J. Wood, and A. Cognata, “Broad-Band, Poly-Harmonic Distortion (PHD) Behavioral Models from Fast Automated Simulations and Large-Signal Vectorial Network Measurements,” IEEE Transactions on Microwave Theory and Techniques Vol. 53. No. 11, November, 2005 pp. 3656-3664

[5] G. Simpson, J. Horn, D. Gunyan, and D. E. Root, “Load-Pull + NVNA = Enhanced X-Parameters for PA Designs with High Mismatch and Technology-Independent Large-Signal Device Models”, 72nd ARFTG Conference, Dec 9-12, 2008

X-Parameters: Measurement, Modeling, and Simulation

January 21, 2008Page 33