ELECTROMAGNETIC FIELDS AND WAVES

Transcription

1 ELECTROMAGNETIC FIELDS AND WAVES MAGDY F. ISKANDER Professor of Electrical Engineering University of Utah Englewood Cliffs, New Jersey 07632

2 CONTENTS PREFACE VECTOR ANALYSIS AND MAXWELL'S EQUATIONS IN INTEGRAL FORM 1.1 Introduction Vector Algebra Coordinate Systems Vector Representation in Various Coordinate Systems Vector Coordinate Transformation Electric and Magnetic Fields Vector Integration Maxwell's Equations in Integral Form Displacement Current General Characteristics of Maxwell's Equations 75 Summary 83 Problems 86

3 iv Contents L. MAXWELL'S EQUATIONS IN DIFFERENTIAL FORM Introduction Vector Differentiation Gradient of Scalar Function Divergence of Vector Field Divergence Theorem Differential Expressions of Maxwell's Divergence Relations Curl of Vector Field Stokes's Theorem Ampere's and Faraday's Laws in Point (Differential) Form Summary of Maxwell's Equations in Differential Forms Continuity Equation and Maxwell's Displacement Current Term Wave Equation in Source Free Region Time Harmonie Fields and Their Phasor Representation Uniform Plane Wave Propagation in Free Space Polarization of Plane Waves 166 Summary 168 Problems MAXWELL'S EQUATIONS AND PLANE WAVE PROPAGATION IN MATERIALS Introduction Characterization of Materials Conductors and Conduction Currents Dielectric Materials and Their Polarization Gauss's Law for Electric Field in Materials Magnetic Materials and Their Magnetization Ampere's Law and Magnetization Current Maxwell's Equations in Material Regions 208

4 Contents 3.9 Boundary Conditions Summary of Boundary Condition for Electric and Magnetic Fields Uniform Plane Wave Propagation in Conductive Medium Electromagnetic Power and Poynting Theorem 248 Summary 261 Problems 263 STATIC ELECTRIC AND MAGNETIC FIELDS Introduction Maxwell's Equations for Static Fields Electrostatic Fields Evaluation of Electric Field E from Electrostatic Potential < Capacitance Electrostatic Energy Density Laplace's and Poisson's Equations Numerical Solution of Poisson's and Laplace's Equations Finite Difference Method Numerical Solution of Electrostatic Problems Method of Moments Magnetostatic Fields and Magnetic Vector Potential Magnetic Circuits Self-Inductance and Mutual Inductance Magnetic Energy 350 Summary 356 Problems 358 NORMAL-INCIDENCE PLANE WAVE REFLECTION AND TRANSMISSION AT PLANE BOUNDARIES Introduction Normal-incidence Plane Wave Reflection and Transmission at Plane Boundary between Two Conductive Media 372

5 VI Contents 5.3 Normal-incidence Plane Wave Reflection at Perfectly Conducting Plane Reflection and Transmission at Multiple Interfaces Reflection Coefficient and Total Field Impedance Solution Procedure Graphical Solution Procedure Using the Smith Chart Quarter- and Half-wavelength Transformers 416 Summary 425 Problems 427 U OBLIQUE INCIDENCE PLANE WAVE REFLECTION AND TRANSMISSION Plane Wave Propagation at Arbitrary Angle Reflection by Perfect Conductor Arbitrary Angle of Incidence Reflection and Refraction at Plane Interface between Two Media: Oblique Incidence Comparison Between Reflection Coefficients T and T ± for Parallel and Perpendicular Polarizations Total Reflection at Critical Angle of Incidence Electromagnetic Spectrum Application to Optics 467 Summary 471 Problems TRANSMISSION LINES Characteristics of Wave Propagation in Transmission Lines Distributed Circuit Representation of Transmission Lines Lossless Line Voltage Reflection Coefficient Transients on Transmission Line 492

6 Contents vii 7.6 Reflection Diagram Tandem Connection of Transmission Lines Pulse Propagation on Transmission Lines Time-Domain Reflectometer Sinusoidal Steady-State Analysis of Transmission Lines Reflections on Transmission Lines with Sinusoidal Excitation Use of Smith Chart Analytical Expression of Transmission-Line Impedance Impedance Matching of Lossless Lines Voltage Standing-Wave Ratio (VSWR) along Transmission Lines Use of VSWR Measurement to Determine Unknown Impedances 562 Summary 573 Problems WAVE GUIDES Introduction Guided Modes in Wave Guides TM Modes in Rectangular Wave Guides TE Modes in Rectangular Wave Guides Field Configurations in Wave Guides Excitation of Various Modes in Wave Guides Energy Flow and Attenuation in Rectangular Wave Guides 616 Summary 630 Problems 632 ANTENNAS Introduction Physical Aspects of Radiation 639

7 VIII Contents 9.3 Radiation from Short Alternating Current Element Basic Antenna Parameters Linear Wire Antennas Antenna Arrays 667 Summary 711 Problems 712 APPENDIXES A Vector Identities and Operations 716 B Units, Multiples, and Submultiples 720 C Trigonometrie, Hyperbolic, and Logarithmic Relations 725 D Free-Space, Atomic, and Material Constants 727 E Cosine C,(x) and Sine S^Ct) Integrals 732 F Answers to Selected Problems 736 INDEX 752