Advanced Techniques in RF Power
Amplifier Design
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Advanced Techniques in RF Power
Amplifier Design
Steve C. Cripps
Artech House
Boston • London www.artechhouse.com
Library of Congress Cataloging-in-Publication Data
Cripps, Steve C.
Advanced techniques in RF power amplifier design / Steve Cripps. p. cm. — (Artech House microwave library)
Includes bibliographical references and index. ISBN 1-58053-282-9 (alk. paper)
1. Power amplifiers. 2. Amplifiers, Radio frequency. I. Title. II. Series.
TK7871.58.P6 C72 |
2002 |
621.384’12—dc21 |
2002016427 |
British Library Cataloguing in Publication Data
Cripps, Steve C.
Advanced techniques in RF power amplifier design. — (Artech House microwave library)
1. Power amplifiers—Design 2. Amplifiers, Radio frequency I. Title
621.3’8412
ISBN 1-58053-282-9
Cover design by Gary Ragaglia
© 2002 ARTECH HOUSE, INC.
685 Canton Street
Norwood, MA 02062
All rights reserved. Printed and bound in the United States of America. No part of this book may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without permission in writing from the publisher.
All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capitalized. Artech House cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting the validity of any trademark or service mark.
International Standard Book Number: 1-58053-282-9
Library of Congress Catalog Card Number: 2002016427
10 9 8 7 6 5 4 3 2 1
Contents
|
Preface |
xi |
|
Acknowledgments |
xv |
1 |
Class AB Amplifiers |
1 |
1.1 |
Introduction |
1 |
1.2 |
Classical Class AB Modes |
2 |
1.3 |
Class AB: A Different Perspective |
9 |
1.4 |
RF Bipolars: Vive La Difference |
16 |
1.4.1 |
A Basic RF BJT Model |
16 |
1.5 |
On Sweet Spots and IM Glitches |
29 |
1.6 |
Conclusions |
31 |
|
Reference |
32 |
2 |
Doherty and Chireix |
33 |
2.1 |
Introduction |
33 |
2.2 |
The Doherty PA |
34 |
2.2.1 |
Introduction and Formulation |
34 |
v
vi Advanced Techniques in RF Power Amplifier Design
2.2.2 |
The Classical Doherty Configuration |
37 |
2.2.3 |
Variations on the Classical Configuration |
42 |
2.2.4 |
Peaking Amplifier Configurations |
49 |
2.2.5 |
Doherty PA Matching Topologies |
52 |
2.2.6 |
The Multiple Doherty PA |
56 |
2.2.7 |
Doherty PA Conclusions |
56 |
2.3 |
The Chireix Outphasing PA |
58 |
2.3.1 |
Introduction and Formulation |
58 |
2.3.2 |
Discussion, Analysis, and Simulation |
62 |
2.3.3 |
Variations |
69 |
2.3.4 |
Chireix: Conclusions |
71 |
|
References |
72 |
3 |
Some Topics in PA Nonlinearity |
73 |
3.1 |
Introduction |
73 |
3.2A Problem, a Solution, and Problems with the
|
Solution |
74 |
3.3 |
Power Series, Volterra Series, and Polynomials |
77 |
3.4 |
Two-Carrier Characterization |
89 |
3.5 |
Memory and IM Asymmetry in RFPAs |
94 |
3.6 |
PAs and Peak-to-Average Ratios |
105 |
3.7 |
Conclusions |
109 |
|
References |
110 |
4 |
Feedback Techniques |
111 |
4.1 |
Introduction |
111 |
4.2 |
Feedback Techniques |
114 |
4.3Amplitude Envelope Feedback: Configuration and
|
Analysis |
121 |
4.4 |
Vector Envelope Feedback |
137 |
|
Contents |
vii |
|
|
|
4.5 |
Low Latency PA Design |
140 |
4.6 |
Variations |
146 |
4.7 |
Conclusions |
150 |
|
References |
151 |
5 |
Predistortion Techniques |
153 |
5.1 |
Introduction |
153 |
5.2 |
Third-Degree PA: Predistortion Analysis |
156 |
5.3 |
PD Characteristic for General PA Model |
163 |
5.4Practical Realization of the Predistorter Function:
|
Introduction |
177 |
5.5 |
Analog Predistorters |
179 |
5.6 |
DSP Predistortion |
187 |
5.7 |
Conclusions |
194 |
|
References |
195 |
6 |
Feedforward Power Amplifiers |
197 |
6.1 |
Introduction |
197 |
6.2 |
The Feedforward Loop |
198 |
6.3 |
AM-PM Correction in the Feedforward Loop |
204 |
6.4 |
Error Insertion Coupling |
208 |
6.5Third-Degree Analysis of the Generalized
|
Feedforward (FFW) Loop |
216 |
6.5.1 |
Formulation and Analysis |
216 |
6.5.2 |
Tracking Errors |
222 |
6.5.3 |
Compression Adjustment |
224 |
6.5.4 |
Third-Degree Analysis: Conclusions |
228 |
6.6 |
Feedforward Loop Simulation |
229 |
6.6.1 |
Effect of AM-PM in Main PA |
231 |
6.6.2 |
Gain Compression Adjustment |
233 |
viii Advanced Techniques in RF Power Amplifier Design
6.6.3 |
EPR Change |
233 |
6.6.4 |
Gain and Phase Tracking |
235 |
6.6.5 |
Multicarrier Simulation |
235 |
6.7 |
Feedforward Loop Efficiency Considerations |
236 |
6.8 |
Adaption and Correction: Closing the Loop |
241 |
6.9 |
Variations |
249 |
6.9.1 |
The Double Feedforward Loop |
249 |
6.9.2 |
A Feedforward-Enhanced Power Combiner |
252 |
6.9.3 |
“Budget” FFW Systems |
253 |
6.10 |
Conclusions |
255 |
|
References |
256 |
7 |
Microwave Power Amplifiers |
257 |
7.1 |
Introduction |
257 |
7.2 |
Broadband Microwave Power Amplifier Design |
259 |
7.2.1 |
Introduction |
259 |
7.2.2 |
Broadband Matching Using Network Synthesis |
259 |
7.2.3 |
Balanced Amplifiers |
270 |
7.2.4 |
Broadband Power Amplifier Design Issues |
273 |
7.3 |
Microwave Circuits and MIC Techniques |
280 |
7.3.1 |
Introduction |
280 |
7.3.2 |
Substrate and Heatsink Materials |
281 |
7.3.3 |
MIC Components and Structures |
283 |
7.4 |
PA Design Using Prematched Modules |
287 |
7.4.1 |
Introduction |
287 |
7.4.2 |
Matching Issues for IMTs |
287 |
7.4.3 |
Biasing Issues for IMTs |
290 |
7.4.4 |
Power Combining of IMTs |
291 |
7.5 |
Distributed Amplifiers |
293 |
7.6 |
Conclusions |
296 |
|
References |
297 |
|
Contents |
ix |
|
|
|
|
Appendix |
299 |
|
Notes |
299 |
|
Selected Bibliography |
300 |
|
Glossary |
301 |
|
About the Author |
305 |
|
Index |
307 |