This page is intentionally left blankMicrowave EngineeringThis page is intentionally left blankMicrowave EngineeringFourth EditionDavid M. PozarUniversity of Massachusetts at AmherstJohn Wiley & Sons, Inc.Vice President & Executive Publisher Don FowleyAssociate Publisher Dan SayreContent Manager Lucille BuonocoreSenior Production Editor Anna MelhornMarketing Manager Christopher RuelCreative Director Harry NolanSenior Designer Jim O’SheaProduction Management Services Sherrill Redd of AptaraEditorial Assistant Charlotte CerfLead Product Designer Tom KulesaCover Designer Jim O’SheaThis book was set in Times Roman 10/12 by AptaraR , Inc. and printed and bound byHamilton Printing. The cover was printed by Hamilton Printing.CopyrightC 2012, 2005, 1998 by John Wiley & Sons, Inc. All rights reserved.No part of this publication may be reproduced, stored in a retrieval system or transmitted inany form or by any means, electronic, mechanical, photocopying, recording, scanning orotherwise, except as permitted under Sections 107 or 108 of the 1976 United States CopyrightAct, without either the prior written permission of the Publisher, or authorization throughpayment of the appropriate per-copy fee to the Copyright Clearance Center, Inc. 222Rosewood Drive, Danvers, MA 01923, website www.copyright.com. Requests to thePublisher for permission should be addressed to the Permissions Department, John Wiley &Sons, Inc., 111 River Street, Hoboken, NJ 07030-5774, (201)748-6011, fax (201)748-6008,website http://www.wiley.com/go/permissions.Founded in 1807, John Wiley & Sons, Inc. has been a valued source of knowledge andunderstanding for more than 200 years, helping people around the world meet their needs andfulfill their aspirations. Our company is built on a foundation of principles that includeresponsibility to the communities we serve and where we live and work. In 2008, welaunched a Corporate Citizenship Initiative, a global effort to address the environmental,social, economic, and ethical challenges we face in our business. Among the issues we areaddressing are carbon impact, paper specifications and procurement, ethical conduct withinour business and among our vendors, and community and charitable support. For moreinformation, please visit our website: www.wiley.com/go/citizenship.Evaluation copies are provided to qualified academics and professionals for review purposesonly, for use in their courses during the next academic year. These copies are licensed andmay not be sold or transferred to a third party. Upon completion of the review period, pleasereturn the evaluation copy to Wiley. Return instructions and a free of charge return shippinglabel are available at www.wiley.com/go/returnlabel. Outside of the United States, pleasecontact your local representative.Library of Congress Cataloging-in-Publication DataPozar, David M.Microwave engineering/David M. Pozar.—4th ed.p. cm.Includes bibliographical references and index.ISBN 978-0-470-63155-3 (hardback : acid free paper)1. Microwaves. 2. Microwave devices. 3. Microwave circuits. I. Title.TK7876.P69 2011621.381’3—dc23 2011033196Printed in the United States of America10987654321PrefaceThe continuing popularity ofMicrowave Engineeringis gratifying. I have received manyletters and emails from students and teachers from around the world with positive comments and suggestions. I think one reason for its success is the emphasis on the fundamentals of electromagnetics, wave propagation, network analysis, and design principlesas applied to modern RF and microwave engineering. As I have stated in earlier editions,I have tried to avoid the handbook approach in which a large amount of information ispresented with little or no explanation or context, but a considerable amount of materialin this book is related to the design of specific microwave circuits and components, forboth practical and motivational value. I have tried to base the analysis and logic behindthese designs on first principles, so the reader can see and understand the process of applying fundamental concepts to arrive at useful results. The engineer who has a firm graspof the basic concepts and principles of microwave engineering and knows how these canbe applied toward practical problems is the engineer who is the most likely to be rewardedwith a creative and productive career.For this new edition I again solicited detailed feedback from teachers and readers fortheir thoughts about how the book should be revised. The most common requests werefor more material on active circuits, noise, nonlinear effects, and wireless systems. Thisedition, therefore, now has separate chapters on noise and nonlinear distortion, and active devices. In Chapter 10, the coverage of noise has been expanded, along with morematerial on intermodulation distortion and related nonlinear effects. For Chapter 11, onactive devices, I have added updated material on bipolar junction and field effect transistors, including data for a number of commercial devices (Schottky and PIN diodes, and Si,GaAs, GaN, and SiGe transistors), and these sections have been reorganized and rewritten.Chapters 12 and 13 treat active circuit design, and discussions of differential amplifiers,inductive degeneration for nMOS amplifiers, and differential FET and Gilbert cell mixers have been added. In Chapter 14, on RF and microwave systems, I have updated andadded new material on wireless communications systems, including link budget, link margin, digital modulation methods, and bit error rates. The section on radiation hazards hasbeen updated and rewritten. Other new material includes a section on transients on transmission lines (material that was originally in the first edition, cut from later editions, andnow brought back by popular demand), the theory of power waves, a discussion of higher
order modes and frequency effects for microstrip line, and a discussion of how to determine unloadedQfrom resonator measurements. This edition also has numerous new or
revised problems and examples, including several questions of the “open-ended” variety.
Material that has been cut from this edition includes the quasi-static numerical analysis of
microstrip line and some material related to microwave tubes. Finally, working from the
original source files, I have made hundreds of corrections and rewrites of the original text.
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vi Preface
Today, microwave and RF technology is more pervasive than ever. This is especially
true in the commercial sector, where modern applications include cellular telephones,
smartphones, 3G and WiFi wireless networking, millimeter wave collision sensors for vehicles, direct broadcast satellites for radio, television, and networking, global positioning
systems, radio frequency identification tagging, ultra wideband radio and radar systems,
and microwave remote sensing systems for the environment. Defense systems continue to
rely heavily on microwave technology for passive and active sensing, communications, and
weapons control systems. There should be no shortage of challenging problems in RF and
microwave engineering in the foreseeable future, and there will be a clear need for engineers having both an understanding of the fundamentals of microwave engineering and the
creativity to apply this knowledge to problems of practical interest.
Modern RF and microwave engineering predominantly involves distributed circuit
analysis and design, in contrast to the waveguide and field theory orientation of earlier
generations. The majority of microwave engineers today design planar components and integrated circuits without direct recourse to electromagnetic analysis. Microwave computeraided design (CAD) software and network analyzers are the essential tools of today’s
microwave engineer, and microwave engineering education must respond to this shift in
emphasis to network analysis, planar circuits and components, and active circuit design.
Microwave engineering will always involve electromagnetics (many of the more sophisticated microwave CAD packages implement rigorous field theory solutions), and students
will still benefit from an exposure to subjects such as waveguide modes and coupling
through apertures, but the change in emphasis to microwave circuit analysis and design
is clear.
This text is written for a two-semester course in RF and microwave engineering for
seniors or first-year graduate students. It is possible to useMicrowave Engineeringwith or
without an electromagnetics emphasis. Many instructors today prefer to focus on circuit
analysis and design, and there is more than enough material in Chapters 2, 4–8, and 10–14
for such a program with minimal or no field theory requirement. Some instructors may wish
to begin their course with Chapter 14 on systems in order to provide some motivational
context for the study of microwave circuit theory and components. This can be done, but
some basic material on noise from Chapter 10 may be required.
Two important items that should be included in a successful course on microwave
engineering are the use of CAD simulation software and a microwave laboratory experience. Providing students with access to CAD software allows them to verify results of the
design-oriented problems in the text, giving immediate feedback that builds confidence and
makes the effort more rewarding. Because the drudgery of repetitive calculation is eliminated, students can easily try alternative approaches and explore problems in more detail.
The effect of line losses, for example, is explored in several examples and problems; this
would be effectively impossible without the use of modern CAD tools. In addition, classroom exposure to CAD tools provides useful experience upon graduation. Most of the
commercially available microwave CAD tools are very expensive, but several manufacturers provide academic discounts or free “student versions” of their
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