ANTENNA THEORY ANALYSIS AND DESIGN THIRD EDITION Constantine A. Balanis A JOHN WILEY & SONS, INC., PUBLICATION Copyright 2005 by John Wiley & Sons, Inc. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey.
Published simultaneously in Canada. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400, fax 978-646-8600, or on the web at www. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008. Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose.
No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.
For general information on our other products and services please contact our Customer Care Department within the U. at 877-762-2974, outside the U. at 317-572-3993 or fax 317-572-4002. Wiley also publishes its books in a variety of electronic formats.
Some content that appears in print, however, may not be available in electronic format. Library of Congress Cataloging-in-Publication Data is available. ISBN: 0-471-66782-X Printed in the United States of America. 10 9 8 7 6 5 4 3 2 1 Preface The third edition of Antenna Theory is designed to meet the needs of electrical engi- neering and physics students at the senior undergraduate and beginning graduate levels, and those of practicing engineers.
The text presumes that the students have knowledge of basic undergraduate electromagnetic theory, including Maxwell’s equations and the wave equation, introductory physics, and differential and integral calculus. Mathemat- ical techniques required for understanding some advanced topics in the later chapters are incorporated in the individual chapters or are included as appendices. The third edition has maintained all of the attractive features of the first two edi- tions, including the three-dimensional graphs to display the radiation characteristics of antennas, especially the amplitude patterns. This feature was hailed as an innovative and first of its kind addition in a textbook on antennas.
Additional graphs have been added to illustrate features of the radiation characteristics of some antennas. However, there have been many new features added to this edition. In particular, ž A new chapter on Smart Antennas (Chapter 16) ž A section on Fractal Antennas (Section 11.6) ž Summary tables of important equations in the respective chapters (Chapters 2, 4, 5, 6, 12–14) ž New figures, photos, and tables ž Additional end-of-the-chapter problems ž CD with the following Multimedia Material: ž Power Point view graphs of lecture notes for each chapter, in multicolor ž End-of-the-chapter Interactive Questionnaires for review (40–65 for each chap- ter) based on Java ž Animations based on Java ž Applets based on Java ž MATLAB programs translated from the FORTRAN programs of the second edition ž A number of new MATLAB programs ž FORTRAN programs from the second edition. The CD is attached to the book, and it will open automatically once inserted in the computer.
It is highly recommended that the reader uses the Internet Explorer (IE) to open the Multimedia Material; other browsers may not perform well. For additional instructions on how to open and use the material in the CD, there is a HELP file in the CD. xiii xiv PREFACE The book’s main objective is to introduce, in a unified manner, the fundamental princi- ples of antenna theory and to apply them to the analysis, design, and measurements of antennas. Because there are so many methods of analysis and design and a plethora of antenna structures, applications are made to some of the most basic and practical con- figurations, such as linear dipoles; loops; arrays; broadband, and frequency-independent antennas; aperture antennas; horn antennas; microstrip antennas; and reflector antennas.
A tutorial chapter on Smart Antennas has been included to introduce the student in a technology that will advance antenna theory and design, and revolutionize wireless communications. It is based on antenna theory, digital signal processing, networks and communications. MATLAB simulation software has also been included, as well as a plethora of references for additional reading. Introductory material on analytical methods, such as the Moment Method and Fourier transform (spectral) technique, is also included.
These techniques, together with the fundamental principles of antenna theory, can be used to analyze and design almost any antenna configuration. A chapter on antenna measurements introduces state-of-the- art methods used in the measurements of the most basic antenna characteristics (pattern, gain, directivity, radiation efficiency, impedance, current, and polarization) and updates progress made in antenna instrumentation, antenna range design, and scale modeling. Techniques and systems used in near- to far-field measurements and transformations are also discussed. A sufficient number of topics have been covered, some for the first time in an under- graduate text, so that the book will serve not only as a text but also as a reference for the practicing and design engineer and even the amateur radio buff.
These include design procedures, and associated computer programs, for Yagi–Uda and log-periodic arrays, horns, and microstrip patches; synthesis techniques using the Schelkunoff, Fourier transform, Woodward–Lawson, Tschebyscheff, and Taylor methods; radiation charac- teristics of corrugated, aperture-matched, and multimode horns; analysis and design of rectangular and circular microstrip patches; and matching techniques such as the binomial, Tschebyscheff, T-, gamma, and omega matches. The text contains sufficient mathematical detail to enable the average undergraduate electrical engineering and physics students to follow, without too much difficulty, the flow of analysis and design. A certain amount of analytical detail, rigor, and thoroughness allows many of the topics to be traced to their origin. My experiences as a student, engineer, and teacher have shown that a text for this course must not be a book of unrelated formulas, and it must not resemble a “cookbook.” This book begins with the most elementary material, develops underlying concepts needed for sequential topics, and progresses to more advanced methods and system configurations.
Each chapter is subdivided into sections or subsections whose individual headings clearly identify the antenna characteristic(s) discussed, examined, or illustrated. A distinguished feature of this book is its three-dimensional graphical illustrations from the first edition, which have been expanded and supplemented in the second and third editions. In the past, antenna texts have displayed the three-dimensional energy radiated by an antenna by a number of separate two-dimensional patterns. With the advent and revolutionary advances in digital computations and graphical displays, an additional dimension has been introduced for the first time in an undergraduate antenna text by displaying the radiated energy of a given radiator by a single three- dimensional graphical illustration.
Such an image, formed by the graphical capabilities of the computer and available at most computational facilities, gives a clear view of PREFACE xv the energy radiated in all space surrounding the antenna. It is hoped that this will lead to a better understanding of the underlying principles of radiation and provide a clearer visualization of the pattern formation in all space. In addition, there is an abundance of general graphical illustrations, design data, references, and an expanded list of end-of-the chapter problems. Many of the principles are illustrated with examples, graphical illustrations, and physical arguments.
Although students are often convinced that they understand the principles, difficulties arise when they attempt to use them. An example, especially a graphical illustration, can often better illuminate those principles. As they say, “a picture is worth a thousand words.” Numerical techniques and computer solutions are illustrated and encouraged. A number of MATLAB computer programs are included in the CD attached to the book.
Each program is interactive and prompts the user to enter the data in a sequential man- ner. Some of these programs are translations of the FORTRAN ones that were included in the first and second editions. However, many new ones have been developed. Every chapter, other than Chapters 3 and 17, have at least one MATLAB computer program; some have as many as four.
The outputs of the MATLAB programs include graphical illustrations and tabulated results. For completeness, the FORTRAN computer pro- grams are also included, although there is not as much interest in them. The computer programs can be used for analysis and design. Some of them are more of the design type while some of the others are of the analysis type.
Associated with each program there is a READ ME file, which summarizes the respective program. The purpose of the Lecture Notes is to provide the instructors a copy of the text figures and some of the most important equations of each chapter. They can be used by the instructors in their lectures but need to be supplemented with additional narratives. The students can use them to listen to the instructors’ lectures, without having to take detailed notes, but can supplement them in the margins with annotations from the lectures.
Each instructor will use the notes in a different way. The Interactive Questionnaires are intended as reviews of the material in each chapter. The student can use them to review for tests, exams, and so on. For each ques- tion, there are three possible answers, but only one is correct.
If the reader chooses one of them and it the correct answer, it will so indicate. However, if the chosen answer is the wrong one, the program will automatically indicate the correct answer. An explanation button is provided, which gives a short narrative on the correct answer or indicates where in the book the correct answer can be found. The Animations can be used to illustrate some of the radiation characteristics, such as amplitude patterns, of some antenna types, like line sources, dipoles, loops, arrays, and horns.
The Applets cover more chapters and can be used to examine some of the radiation characteristics (such as amplitude patterns, impedance, bandwidth, etc.) of some of the antennas. This can be accomplished very rapidly without having to resort to the MATLAB programs, which are more detailed. For course use, the text is intended primarily for a two-semester (or two- or three- quarter) sequence in antenna theory. The first course should be given at the senior undergraduate level, and should cover most of the material in Chapters 1 through 7, and Chapters 16 and 17.
The material in Chapters 8 through 16 should be covered in a beginning graduate-level course. Selected chapters and sections from the book can be covered in a single semester, without loss of continuity. However, it is almost essential that most of the material in Chapters 2 through 6 be covered in the first course and before proceeding to any more advanced topics. To cover all the material of the text xvi PREFACE in the proposed time frame would be, in some cases, a very ambitious task.
Sufficient topics have been included, however, to make the text complete and to give the teacher the flexibility to emphasize, deemphasize, or omit sections or chapters. Some of the chapters and sections can be omitted without loss of continuity. In the entire book, an ej ωt time variation is assumed, and it is suppressed.