A timely and authoritative update to a leading text on the applied electromagnetics of transmission lines
In the newly revised second edition of Applied Electromagnetics: Early Transmission Lines Approach, experienced engineer and professor Stuart Wentworth delivers an up-to-date and authoritative discussion of the electromagnetic foundations of signal transmission. The book explains practical applications for wireless systems, transmission lines, waveguides (including optical fiber), and antennas.
Wentworth provides a detailed theoretical grounding of the subject and combines it with hands-on MATLAB simulations available on the web that help students understand critical concepts.
Brand-new end-of-chapter problems at a broad range of difficulty levels Many more drill and example problems Worked solutions provided on the companion website Extensively updated material as well as entirely new material on metamaterials and patch antennas
Perfect for undergraduate students of electrical engineering, Applied Electromagnetics: Early Transmission Lines Approach will also benefit researchers and educators in electrical engineering.
About the Author xi
Preface xii
Acknowledgments xvii
About the Companion Website xviii
Chapter 1
Introduction 1
1.1 Electromagnetic Fields 3
Electric Fields 3
Magnetic Fields 6
Field Linkage 8
1.2 Electromagnetic Spectrum 9
1.3 Numeric Considerations 11
1.4 Wireless Communications 14
1.5 Wave Fundamentals 16
1.6 Phasors 22
Summary 25
Problems 25
Chapter 2
Transmission Lines 27
2.1 Distributed-Parameter Model 29
Coaxial Cable 31
Telegraphists Equations 35
2.2 Time-Harmonic Waves on Transmission Lines 37
Characteristic Impedance 41
Lossless Line 43
2.3 Power Transmission 45
2.4 Terminated T-Lines 49
Voltage Standing Wave Ratio 50
Input Impedance 52
Complex Loads 54
Special Terminations 55
2.5 The Complete Circuit 58
2.6 The Smith Chart 63
T-Line Calculator 69
Impedance Measurement 73
2.7 Impedance Matching 79
Quarter-Wave Transformer 79
Simple Matching with the Smith Chart 80
Admittance of Shunt Stubs 83
Shunt-Stub Matching 87
Lumped Element Matching 92
2.8 Microstrip 102
Other Planar T-lines 107
2.9 Transients 108
Pulse Response 113
Practical Application: Schottky Diode Terminations 116
Reactive Loads 117
Time Domain Reflectometry 120
2.10 Dispersion 123
Fourier Series of a Rectangular Pulse 124
Fourier Series of a Trapezoidal Pulse 125
Dispersion of Trapezoidal Pulse 127
Summary 128
Suggested References 130
Problems 130
Chapter 3
Electrostatics 138
3.1 Vectors in The Cartesian Coordinate System 140
Differential Elements 145
3.2 Coulombs Law 146
Electric Field Intensity 151
Field Lines 153
3.3 Spherical Coordinate System 153
3.4 Line Charges and The Cylindrical Coordinate System 159
Infinite Length Line of Charge 161
Ring of Charge 167
3.5 Surface and Volume Charge 169
Volume Charge 174
Practical Application: Laser Printer 176
3.6 Electric Flux Density 177
3.7 Gausss Law and Applications 182
Coaxial Cable 187
3.8 Divergence and The Point Form of Gausss Law 190
3.9 Electric Potential 196
Gradient 201
3.10 Conductors and Ohms Law 205
Current and Current Density 207
Joules Law 210
3.11 Dielectrics 212
Practical Application: Electret Microphone 217
3.12 Boundary Relations 218
3.13 Boundary Value Problems 223
3.14 Capacitance 231
Electrostatic Potential Energy 235
Practical Application: Electrolytic Capacitors 237
Summary 238
Problems 240
Chapter 4
Magnetostatics 250
4.1 Magnetic Fields and The Cross Product 251
Oersteds Experiment 258
4.2 Biot-Savarts Law 258
Solenoid 264
Surface and Volume Current Densities 267
4.3 Amperes Circuit Law 270
4.4 Curl and The Point Form of Amperes Circuit Law 280
Stokes Theorem 284
4.5 Magnetic Flux Density 287
4.6 Magnetic Forces 289
Force on a Current Element 292
Magnetic Torque and Moment 296
Practical Application: Loudspeakers 301
4.7 Magnetic Materials 303
4.8 Boundary Conditions 309
4.9 Inductance and Magnetic Energy 314
Mutual Inductance 319
Magnetic Energy 321
4.10 Magnetic Circuits 326
Electromagnets 333
Practical Application: Maglev 335
Summary 337
Problems 340
Chapter 5
Dynamic Fields 348
5.1 Current Continuity and Relaxation Time 349
5.2 Faradays Law and Transformer Emf 352
Transformer EMF 355
Transformers 359
Point Form of Faradays Law 362
5.3 Faradays Law and Motional Emf 362
Generators 368
5.4 Displacement Current 370
5.5 Maxwells Equations 375
5.6 Lossless Tem Waves 376
5.7 Time-Harmonic Fields and Phasors 381
Summary 385
Problems 386
Chapter 6
Plane Waves 391
6.1 General Wave Equations 393
Time-Harmonic Wave Equations 394
Propagating Fields Relation 398
6.2 Propagation in Lossless, Charge-Free Media 400
6.3 Propagation in Dielectrics 402
Low-Loss Dielectrics 405
Loss Tangent 406
6.4 Propagation in Conductors 408
Current in Conductors 411
6.5 The Poynting Theorem and Power Transmission 416
UPW Power Transmission 418
6.6 Polarization 421
Linear Polarization 421
Circular Polarization 424
Elliptical Polarization 425
6.7 Reflection and Transmission at Normal Incidence 427
General Case 428
Standing Waves 433
6.8 Reflection and Transmission at Oblique Incidence 434
TE Polarization 436
TM Polarization 442
6.9 Waves in Metamaterials 448
Backward Waves 449
Negative Refraction 452
Summary 453
Suggested Bibliography 455
Problems 455
Chapter 7
Waveguides 461
7.1 Dielectric Waveguide 463
Boundary Reflection 467
Dielectric Waveguide Modes 469
Field Patterns 476
7.2 Rectangular Waveguide Fundamentals 478
Wave Propagation 482
Waveguide Impedance 486
Waveguide Field Equations 487
Practical Application: Microwave Ovens 490
7.3 Optical Fiber 492
Numerical Aperture 496
Signal Degradation 498
Attenuation 498
Graded-Index Fiber 499
7.4 Fiber-Optic Communication Systems 500
Optical Sources 501
Optical Detectors 503
Repeaters and Optical Amplifiers 505
Connections 506
7.5 Optical Link Design 508
Power Budget 508
Rise-Time Budget 509
Summary 513
Suggested Bibliography 515
Problems 515
Chapter 8
Antennas 518
8.1 General Properties 520
Radiated Power 520
Radiation Patterns 521
Directivity 524
Impedance and Efficiency 528
Parabolic Reflectors 532
Commercial Antenna 532
8.2 Electrically Short Antennas 535
Vector Magnetic Potential 535
The Hertzian Dipole 539
Small Loop Antenna 544
8.3 Dipole Antennas 546
Derivation of Fields 546
Half-Wave Dipole 549
Folded Dipole Antennas 555
8.4 Monopole Antennas 555
Image Theory 556
Antenna Properties 557
Practical Considerations 559
8.5 Patch Antennas 560
8.6 Antenna Arrays 569
Pair of Hertzian Dipoles 570
N-Element Linear Arrays 577
Parasitic Arrays 579
Microstrip Patch Arrays 581
8.7 The Friis Transmission Equation 586
Polarization Loss Factor 591
The General Friis Transmission Equation 593
Circular Polarization 595
Receiver Matching 597
8.8 Radar 599
Doppler Frequency Shift 602
Summary 603
Suggested Bibliography 607
Problems 608
Appendix A
Vector Relations 615
Appendix B
Coordinate System Transformations 618
Appendix C
Complex Numbers 622
Appendix D
Integrals, Conversions, and Constants 624
Appendix E
Material Properties 627
Index 631
Stuart M. Wentworth, PhD, is Assistant Professor Alumni at Auburn University, having retired in 2023 after 33 years of service in the Electrical and Computer Engineering Department. His research focused on antennas, microwave circuit and interconnect modeling, and high frequency material characterization.
