LIST OF APPLICATIONS AND NATURAL PHENOMENA Plasma 37 Measurement of wavelength 146 Radio waves from the sun 45 Slotted coaxial lines 147 Solar energy 47 Impedance matching by shunt Extraterrestrial sources 47 . admittance, 181 Remote sensing 47 Microwave inductors and 'adio interferences from capacitors 182 thunderstorms 48 Digital-to-analog converter 190 Human exposure to RF electromagnetic Electromagnetic radiation from cellular radiation 53 telephones 222 Reception ofradio and television Josephson junctions 245 signals 60 Phased array 245 Eye detection of polarized light 61 Very long baseline arrays 251 Glareless headlight system for Scattering oflight 264 automobiles 61 Why the sky is blue 265 Stereoscopic pictures with polarized Holography 268 light 62 Red shift 278 Communication system using orthogonal Doppler frequency shift of a wave polarizations 62 reflected from a moving target 279 Radio communication between Doppler radar 281 submarines 69 Frequency-modulated continuous-wave Microwave ovens 72 Doppler radar 282 The tails of comets 76 How to produce a circularly polarized Brewster window 97 light 284 Reflection from the ionosphere 101 Dichroism and polarized Reflection ofelectromagnetic waves from sunglasses 286 skin 102 Liquid crystals 286 Fabry-Perot resonators 106 Lightning rod 318 Standing wave in front of a dielectric The Van de Graaff generator 323 medium 107 Triboelectricity 325 Microwave reflectors 109 Electrostatic separation 336 Reflection by grating ofparallel Electric corona 339 wires 111 Electrostatic filter 341 Microstrips or striplines 124 Electrostatic paint spraying 342 Ionosphere-earth waveguide 125 Xerography 343 Project Seafarer 127 Laser printer 344 X-band waveguide 131 Cathode ray tube 348 Frequency meter 137 Ion thruster 350 Optical fibers 142 Ink-jet printer 353 Dielectric breakdown 364 Magnetic-disk memory 505 Electrostatic adhesive surface 372 The sea floor as a magnetic Electrophoresis 373 memory 507 Electric fields due to power lines 404 Thermomagnetic copying 508 Well logging 437 Condenser microphones 530 Magnetic fields due to power Rail guns 549 lines 459 Induction heating 552 Isotope separation 465 Nondestructive evaluation of Cyclotron 466 pipes 555 Hall effect 468 Betatron s 562 Effect ofearth's magnetic field on CRT Homopolar generators 564 display 471 AC generators 566 DC motor 475 Induction motors 570 Permanent magnet 496 Synchronous motors 574 Earth's magnetic field 499 The magneplane 576 Magnetic-core memory 501 1 f APPLIED ELECTROMA Third Edition Liang Chi Shen University ofHouston )in Au Kong Massachusetts Institute ofTechnology P S PWS Publishing Company W ICT P An International Thomson Publishing Comp . . Boston Albany Bonn .Cincinna.ti Detroit London Mexico City New York Paris San Francisco Singapo Washington I PWS PUBLISHING COMPANY 20 Park Plaza, Boston, MA 02116-4324 Copyright 1987by PWS Publishers. Copyright 1995by PWS Publishing Company, a division ofInternational Thomson Publishing Inc. All rights reserved. No part ofthis book may—be reproduced, stored in a retrieval system, or transcribed in any fo—rm or by any means electronic, mechanical, photocopying, recording, or otherwise without the prior written permission ofPWS Publishing Company. '" IOTP International Thomson Publishing International Thomson Editores The traderttark ITP is used under license Campos Eliseos 385,Piso 7 Col. Polanco For more information, contact 11560Mexico C.F.,Mexico PWS Publishing Co. International Thomson Publishing GmbH 20 Park Plaza Konigswinterer Strasse 418 Boston, MA 02116 53227 Bonn, Germany International Thomson Publishing Europe International Thomson Publishing Asia Berkshire House 168-173 221 Henderson Road High Holborn g05-10Henderson Building London WC1V7AA Singapore 0315 England International Thomson Publishing Japan Thomas Nelson Australia Hirakawacho Kyyowa Building, 31 102Dodds Street 2-2-1 Hirakawacho South Melbourne, 3205 Chiyoda-ku, Tokyo 102 Victoria, Australia Japan Nelson Canada 1120Birchmount Road Library ofCongress Cataloging-in-Publication Data Scarborough, Ontario Canada M1K5G4 Shen, Liang Chi. Applied electromagnetism/Liang Chi Shen, Jin Au Kong.—3rd ed. Sponsoring Editor: Tom Robbins p. cm. Assistant Editor: Ken Morton Includes bibliographical references (p. )and index. Editorial Assistant: Lai Wong ISBN0-534-94722-0 (alk. paper) Production and Interior Design: Pamela Rockwell 1. Electric engineering. 2. Electromagnetic theory. I. Kong, .. Marketing Manager: Nathan Wilbur Jin Au, 1942— II. Title. Manufacturing Coordinator: Lisa Flanagan TK 1—53.S475 1995 Compositor: Santype International Ltd 621.3 dc20 95-47 Cover Printer: Henry Sawyer Company CIP Text Printer and Binder: Quebecor, Martinsburg This book is printed on recycled, acid-free paper. Printed and bound in th—e United States ofAmerica. 10987654 99 To our parents: How could a blade ofgrass Repay the warmth from the spring sun — Meng Chio (751-814) COURSE OPTIONSIAPPLIED ELECTROMAGNETISM* Complex Vectors, Chapter 1 Maxwell's Equations, Chapter 2 Uniform Plane Waves, Chapter 3 Reflection and Transmission of Waves, Chapter 4 Waveguides and Resonators, Transmission Lines, Chapter 5 Antennas, Chapter 7 Chapter 6 Topics in Waves, Chapter 8 Electrostatic Fields, Chapter 9 Electric Force and Energy, Chapter 10 Solution Techniques, Direct Currents, Chapter 11 Chapter 12 Magnetostatic Fields, Chapter 13 Electroquasistatic Fields, Magnetic Materials and Magnetic Magnetoquasistatic Fields, Chapter 15 Circuits, Chapter 14 Chapter 16 s The nine chapters in the central column may be covered in a one-semester course. IY CONTENTS Notations, Symbols, and Units xiii COMPLEX VECTORS I I 1.1 Complex Algebra I 1.2 Complex Representation of Time-Harmonic Scalars 4 1.3 Real Vectors 7 1.4 Complex Vectors 4 I 1.5 Time Averages 7 I Problems 9 I 2 MAXWELL'S EQUATIONS 23 2.1 Maxwell's Equations 23 2.2 Constitutive Relations 34 2.3 Maxwell's Equations for Time-Harmonic Fields 36 2.4 Lorentz Force Law 37 2.5 Poynting's Theorem 39 Problems 42 I 3 UNIFORM PLANE WAVES 45 3.1 Electromagnetic Sources 45 3.2 Uniform Plane Waves in Free Space 48 3.3 Polarization 56 3.4 Plane Waves in Dissipative Media 62 Y 1 VI Contents 3.5 Radiation Power and Radiation Pressure 72 Problems 80 4 REFLECTION AND TRANSMISSION OF WAVES 84 4.1 Boundary Conditions 84 4.2 Reflection and Transmission at a Dielectric Interface 88 4.3 Standing Waves 103 Problems 112 5 WAVEG UIDES AND RESONATORS 119 5.1 Parallel-Plate Waveguides 119 5.2 Rectangular Waveguides and Resonators 128 5.3 Dielectric Slab Waveguides 138 5.4 Coaxial Lines 143 Problems 149 I 6 TRANSMISSION LINES 155 6.1 Concept ofVoltage, Current, and Impedance 155 6.2 Transmission-Line Equations 161 6.3 Impedances 165 6.4 Generalized Reflection Coeflicient and Smith Chart 168 6.5 Transients on Transmission Lines 187 Problems 206 7 ANTENNAS 210 7.1 Vector and Scalar Potential Functions 210 7.2 Fields of an Infinitesimal Antenna 212 7.3 Linear Antennas 224 7.4 Array Antennas 231 Problems 254 Ij Contents VII 8 TOPICS IN WAVES 259 8.1 Rayleigh Scattering 259 8.2 Fourier Optics and Holography 265 8.3 Gaussian Beam 272 8.4 Doppler Effect 276 8.5 Plane Waves in Anisotropic Media 283 Problems 288 9 ELECTROSTATIC FIELDS 291 9.1 Electrostatic Potential 291 9.2 Electrostatic Fields 297 9.3 Gauss'aw and Its Applications —304 9.4 Calculation of Potential from E Field Line Integral 315 Problems 327 IQ ELECTRIC FORCE AND ENERGY 331 10.1 Electric Force 331 10.2 Work and Energy 345 10.3 Capacitance 359 Problems 375 SOLUTION TECHNIQUES I I 380 11.1 Poisson and Laplace Equations 380 11.2 Image Method 389 11.3 Method of Separation ofVariables 407 Problems 418 I2 DIRECT CURRENTS 424 12.1 Ohm's Law 424 12.2 Analogy Between Direct Current and Electrostatic Field 429 Problems 440 I