Distortion in Rf Power Amplifiers (Artech House Microwave Library)

269 Pages·2003·2.02 MB·English

by  Joel Vuolevi

Distortion in RF Power Amplifiers
ForalistingofrecenttitlesintheArtechHouseMicrowaveLibrary,turntotheback
ofthisbook.
Distortion in RF Power Amplifiers
Joel Vuolevi
Timo Rahkonen
Artech House
Boston • London
www.artechhouse.com
LibraryofCongressCataloging-in-PublicationData
Vuolevi,Joel.
DistortioninRFpoweramplifiers/JoelVuolevi,TimoRahkonen.
p.cm.—(ArtechHousemicrowavelibrary)
Includesbibliographicalreferencesandindex.
ISBN1-58053-539-9(alk.paper)
1.Poweramplifiers.2.Amplifiers,Radiofrequency.3.Electricdistortion—Prevention.
I.Rahkonen,Timo.II.Title.III.Series.
TK7871.58.P6V792003
621.384'12—dc21
2002043669
BritishLibraryCataloguinginPublicationData
Vuolevi,Joel
DistortioninRFpoweramplifiers.—(ArtechHouse
microwavelibrary)
1.Poweramplifiers 2.Amplifiers,Radiofrequency 3.Radio—
Interference
I.Title II.Rahkonen,Timo
621.3'8412
ISBN1-58053-539-9
CoverdesignbyGaryRagaglia
©2003ARTECHHOUSE,INC.
685CantonStreet
Norwood,MA02062
Allrightsreserved.PrintedandboundintheUnitedStatesofAmerica.Nopartofthisbook
may be reproduced or utilized in any form or by any means, electronic or mechanical, in-
cludingphotocopying,recording,orbyanyinformationstorageandretrievalsystem,with-
outpermissioninwritingfromthepublisher.
Alltermsmentionedinthisbookthatareknowntobetrademarksorservicemarkshave
been appropriately capitalized. Artech House cannot attest to the accuracy of this informa-
tion.Useofaterminthisbookshouldnotberegardedasaffectingthevalidityofanytrade-
markorservicemark.
InternationalStandardBookNumber:1-58053-539-9
LibraryofCongressCatalogCardNumber:2002043669
10987654321
Contents
Acknowledgments ix
Chapter 1 Introduction 1
1.1 Motivation ....................................................................1
1.2 Historical Perspective ...................................................2
1.3 Linearization and Memory Effects ...............................3
1.4 Main Contents of the Book ...........................................4
1.5 Outline of the Book ......................................................6
References...................................................................................8
Chapter 2 Some Circuit Theory and Terminology 9
2.1 Classification of Electrical Systems ...........................10
2.1.1 Linear Systems and Memory............................ 10
2.1.2 Nonlinear Systems........................................... 13
2.1.3 Common Measures of Nonlinearity.................. 15
2.2 Calculating Spectrums in Nonlinear Systems .............18
2.3 Memoryless Spectral Regrowth ..................................21
2.4 Signal Bandwidth Dependent Nonlinear Effects .........25
2.5 Analysis of Nonlinear Systems ...................................27
2.5.1 Volterra Series Analysis................................... 28
2.5.2 Direct Calculation of Nonlinear Responses...... 30
2.5.3 Two Volterra Modeling Approaches................ 34
v
vi Distortion in RF Power Amplifiers
2.6 Summary ....................................................................39
2.7 Key Points to Remember ............................................41
References.................................................................................41
Chapter 3 Memory Effects in RF Power Amplifiers 43
3.1 Efficiency ...................................................................43
3.2 Linearization ..............................................................45
3.2.1 Linearization and Efficiency............................ 45
3.2.2 Linearization Techniques................................. 46
3.2.3 Linearization and Memory Effects................... 48
3.3 Electrical Memory Effects ..........................................51
3.4 Electrothermal Memory Effects ..................................56
3.5 Amplitude Domain Effects .........................................59
3.5.1 Fifth-Order Analysis Without Memory Effects 60
3.5.2 Fifth-Order Analysis with Memory Effects...... 62
3.6 Summary ....................................................................66
3.7 Key Points to Remember ............................................67
References.................................................................................68
Chapter 4 The Volterra Model 71
4.1 Nonlinear Modeling ...................................................71
4.1.1 Nonlinear Simulation Models........................... 72
4.1.2 The Properties of the Volterra Models............. 75
4.2 Nonlinear I-V and Q-V Characteristics ......................77
4.2.1 I -V -V Characteristic................................ 78
C BE CE
4.2.2 g and r ........................................................ 82
pi bb
4.2.3 Capacitance Models......................................... 82
4.3 Model of a Common-Emitter BJT/HBT Amplifier .....84
4.3.1 Linear Analysis................................................ 84
4.3.2 Nonlinear Analysis........................................... 87
4.4 IM3 in a BJT CE Amplifier ........................................95
4.4.1 BJT as a Cascade of Two Nonlinear Blocks..... 95
4.4.2 Detailed BJT Analysis.................................... 102
4.5 MESFET Model and Analysis ..................................109
4.6 Summary ..................................................................115
4.7 Key Points to Remember ..........................................117
References...............................................................................118
Contents vii
Chapter 5 Characterization of Volterra Models 123
5.1 Fitting Polynomial Models .......................................124
5.1.1 Exact and LMSE Fitting................................. 124
5.1.2 Effects of Fitting Range................................. 126
5.2 Self-Heating Effects .................................................127
5.2.1 Pulsed Measurements..................................... 129
5.2.2 Thermal Operating Point................................ 131
5.3 DC I-V Characterization ..........................................133
5.3.1 Pulsed DC Measurement Setup...................... 133
5.3.2 Fitting I-V Measurements.............................. 134
5.4 AC Characterization Flow ........................................136
5.5 Pulsed S-Parameter Measurements ...........................137
5.5.1 Test Setup...................................................... 137
5.5.2 Calibration..................................................... 139
5.6 De-embedding the Effects of the Package ................140
5.6.1 Full 4-Port De-embedding.............................. 141
5.6.2 De-embedding Plain Bonding Wires.............. 143
5.7 Calculation of Small-Signal Parameters ...................145
5.8 Fitting the AC Measurements ...................................147
5.8.1 Fitting of Nonlinear Capacitances.................. 147
5.8.2 Fitting of Drain Current Nonlinearities.......... 149
5.9 Nonlinear Model of a 1-W BJT ................................152
5.10Nonlinear Model of a 1-W MESFET ........................155
5.11Nonlinear Model of a 30-W LDMOS .......................160
5.12Summary ..................................................................165
5.13Key Points to Remember ..........................................166
References...............................................................................167
Chapter 6 Simulating and Measuring Memory Effects 171
6.1 Simulating Memory Effects ......................................172
6.1.1 Normalization of IM3 Components................ 172
6.1.2 Simulation of Normalized IM3 Components.. 175
6.2 Measuring the Memory Effects ................................180
6.2.1 Test Setup and Calibration............................. 181
6.2.2 Measurement Accuracy.................................. 184
6.2.3 Memory Effects in a BJT PA......................... 185
6.2.4 Memory Effects in an MESFET PA............... 187
6.3 Memory Effects and Linearization ...........................187
6.4 Summary ..................................................................190
viii Distortion in RF Power Amplifiers
6.5 Key Points to Remember ..........................................191
References...............................................................................192
Chapter 7 Cancellation of Memory Effects 193
7.1 Envelope Filtering ....................................................194
7.2 Impedance Optimization ..........................................198
7.2.1 Active Load Principle.................................... 199
7.2.2 Test Setup and Its Calibration........................ 202
7.2.3 Optimum Z at the Envelope Frequency
BB
Without Predistortion ..................................203
7.2.4 Optimum Z at the Envelope Frequency
BB
with Predistortion........................................ 204
7.3 Envelope Injection ...................................................207
7.3.1 Cancellation of Memory Effects in a
CE BJT Amplifier ........................................209
7.3.2 Cancellation of Memory Effects in a
CS MESFET Amplifier ...............................211
7.4 Summary ..................................................................217
7.5 Key Points to Remember ..........................................219
References...............................................................................220
Appendix A: Basics of Volterra Analysis 221
Reference ................................................................................225
Appendix B: Truncation Error 227
Appendix C: IM3 Equations for Cascaded Second-Degree
Nonlinearities 231
Appendix D: About the Measurement Setups 245
Reference ................................................................................247
Glossary 249
About the Authors 253
Index 255
Acknowledgments
Manypersonsandorganizationsdeservewarmthanksformakingthisbook
a reality. To mention a few, Jani Manninen has made many of the
measurements and test setups presented in this book, Janne Aikio
contributed much to the characterization measurement techniques, and
Antti Heiskanen contributed to the higher order Volterra analysis. Mike
Faulkner and Lars Sundström originally introduced us to this linearization
business. Veikko Porra and Jens Vidkjaer pointed out several important
topicstoprobefurther.Thegrammarandstyleofthisbookandtheoriginal
publications on which it is mostly based have been checked by Janne
Rissanen, Malcolm Hicks, and Rauno Varonen. Also, David Choi spent a
lot of time with the text to make it more readable and fluent.
The financial and technical support of TEKES (National Technology
Agency of Finland), Nokia Networks, Nokia Mobile Phones, Elektrobit
Ltd, and Esju Ltd is gratefully acknowledged. The work has also been
supported by the Graduate School in Electronics, Telecommunications and
Automation (GETA) and the following foundations: Nokia Foundation,
Tauno Tönningin säätiö, and Tekniikan edistämissäätiö.
Last but most important, we would like to thank our very nearest:
Katja, Aleksi, Kaarina, and Antti Vuolevi, Paula Pesonen, and Kaija,
Heikki, and Ismo Rahkonen.
ix