Introduction to Antenna Analysis Using EM Simulators (Antennas and Propagation)

292 Pages·2011·13.18 MB·English

by  Hiroaki Kogure

Introduction to Antenna Analysis
Using EM Simulators
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Introduction to Antenna Analysis
Using EM Simulators
Hiroaki Kogure
Yoshie Kogure
James C. Rautio
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A catalog record for this book is available from the U.S. Library of Congress.
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Cover design by Adam Renvoize
ISBN 13: 978-1-60807-157-9
Original Japanese edition
Denjikai Simulator de Manabu Antenna Nyuumon
By Hiroaki KOGURE and Yoshie KOGURE
Copyright © 2010 by Hiroaki KOGURE and Yoshie KOGURE
Published by Ohmsha, Ltd.
3-1 Kanda Nishikicho, Chiyodaku, Tokyo, Japan
English language editon
Copyright © 2011 by Artech House
Translation rights arranged with Ohmsha, Ltd.
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may be reproduced or utilized in any form or by any means, electronic or mechanical, includ-
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10 9 8 7 6 5 4 3 2 1
Contents
Preface xiii
1 The Antennas Around Us 1
1.1 What Is an Electrical Circuit? 1
1.1.1 Circuit with Two Parallel Lines 1
1.1.2 Role of the Ground Conductor 2
1.1.3 Antennas at the Edge of a Substrate 2
1.2 Just Exactly What Is the Antenna? 3
1.2.1 Television Antennas 4
1.2.2 Antenna in a Radio-Synchronized Clock 5
1.2.3 Is the Coil of a Radio-Synchronized Clock an Antenna? 6
1.3 Fundamental Form of Antennas 7
1.3.1 The Yagi Antenna 7
1.3.2 Electromagnetic Simulation for Antennas 9
1.3.3 Fundamental Forms of Antennas 25
1.4 What Are Near and Far Fields? 29
1.4.1 Boundary Between Near Field and Far Field 29
2 Antennas and Radio Waves 31
2.1 Great Inventions 31
2.1.1 The Experiments of Hertz 31
v
vi Introduction to Antenna Analysis Using EM Simulators
2.1.2 Hertz’s Receiving Equipment 31
2.1.3 Simulation of Hertz’s Transmitting Equipment 33
2.1.4 Transforming Parallel Plate Capacitors into Antennas 36
2.1.5 Simulation of Hertz’s Receiving Equipment 37
2.1.6 Experiments by Dr. Nagaoka 40
2.2 The Development of Various Antennas 41
2.2.1 Appearance of Marconi 42
2.2.2 History of Ungrounded Antennas 43
2.2.3 Aperture Antennas 44
2.2.4 The Role of Ground 46
2.2.5 Current on an Artificial Ground 50
2.3 Electric Field, Magnetic Field, Electromagnetic
Field, and the Electromagnetic Wave 50
2.3.1 Electric Field Near Hertz’s Dipole 50
2.3.2 Radiation from a Dipole Antenna 50
2.3.3 Magnetic Field Near the Dipole Antenna 52
2.3.4 Electromagnetic Field and the Electromagnetic Wave 53
2.3.5 Difficulty of Near-Field Problems 54
2.4 Antenna Design by Using EM Simulators 55
2.4.1 Antennas on PCB 55
2.4.2 Antennas Created by Using EM Simulators 56
2.4.3 Design of Electric Field Detection Type Antennas 57
2.4.4 Simulation of a Small Loop for an Integrated
Circuit Tag Antenna 58
3 Wire Antennas 63
3.1 Fundamentals of a Dipole Antenna 63
3.1.1 Standing Wave on a Linear Dipole Antenna 63
3.1.2 Designing the Element Length 65
3.1.3 A Dipole Antenna on a Substrate 65
3.1.4 Parameterization 66
3.1.5 Examining the Impedance 69
3.2 Fundamentals of a Loop Antenna 71
3.2.1 Simulation for a Quad Antenna 71
3.2.2 What Is a Magnetic Loop Antenna? 72
Contents vii
3.2.3 Simulation of the Small Loop Antenna 75
3.2.4 Matching the Small Loop to 50Ω 77
3.3 Fundamentals of the Yagi-Uda Antenna 79
3.3.1 Fundamentals of a Reflector 79
3.3.2 Fundamentals of a Director 81
3.3.3 Simulation of the Yagi-Uda Antenna 82
3.4 Importance of Antenna Input Impedance 88
3.4.1 A 50-Ohm Dipole Antenna 88
3.4.2 What is a BALUN? 90
3.4.3 What is the Matched Load? 92
3.4.4 Need for a Matching Circuit 93
3.5 Instruments for Measurement of Input Impedance 93
4 Antennas on Substrates 97
4.1 Substrate Dielectrics and Wavelength Shortening 97
4.1.1 Dipole Antenna on a Substrate 97
4.1.2 Wavelength Shortening Effect of Dielectrics 97
4.1.3 Investigating Wavelength Shortening Effect in
an MSL 100
4.2 Fundamentals of an Inverted L Antenna 102
4.2.1 What Is an Inverted L Antenna? 103
4.3 Fundamentals of a Patch Antenna 109
4.3.1 A Patch Antenna for Global Positioning Systems 110
4.3.2 Electromagnetic Field Around a Patch Antenna 111
4.3.3 Determining Dimensions of a Patch Antenna 114
4.3.4 A Patch Antenna on a Substrate 117
4.3.5 Matching Method 1 119
4.3.6 Fine Adjustment of a Feed Point 122
4.3.7 Matching Method 2 124
4.4 Effects of Dielectric Materials 127
4.4.1 Effective Permittivity of Microstrip Lines 129
4.4.2 Loss Tangent of Dielectrics 131
viii Introduction to Antenna Analysis Using EM Simulators
4.5 Effect of Magnetic Materials 131
4.5.1 Characteristics of Magnetic Materials 132
5 Traveling Wave Antennas 133
5.1 Turning Transmission Lines into Antennas 133
5.1.1 Two Parallel Lines Turn into Antennas 133
5.1.2 The Point of Transition Between Transmission Lines
and Antennas 136
5.1.3 Conditions for a Pure Traveling Wave 136
5.2 Antennas That Do Not Resonate 139
5.2.1 The Tapered Slot Antenna 139
5.2.2 Matching the TSA 143
5.3 Fundamentals of a Bow Tie Antenna 143
5.3.1 The Biconical Antenna 144
5.3.2 Finite Length Biconical Antenna 144
5.3.3 The Impact of Truncating a Traveling Wave Antenna 146
5.3.4 Simulation of a Bow Tie Antenna 147
5.3.5 Skeleton-Type Bow Tie Antenna 148
5.3.6 A Thinner Element Frame 151
5.3.7 Miniaturization Using Triangular Antennas 154
5.3.8 Flare Angle and Bandwidth 158
5.3.9 A Thin Element Triangular Antenna 159
6 Antennas for RFID Systems 163
6.1 RFID Systems Based on Electromagnetic Induction 163
6.1.1 Faraday’s Law of Electromagnetic Induction 163
6.1.2 Self-Inductance of a Coil 164
6.1.3 What Is a Mutual Inductance? 166
6.1.4 Coupling Coefficient Between Reader–Writer’s
Coil and the Tag Coil 166
6.1.5 Finding the Coupling Coefficient κ Using
Sonnet Lite 168
6.1.6 13.56-MHz Antenna (Coil) 169
6.2 UHF RFID Tag Antennas 173
Contents ix
6.2.1 Application of an RFID Tag 173
6.2.2 Half-Wavelength Dipole Antenna for the UHF Band 174
6.2.3 Broadband Techniques 175
6.2.4 Changing the Element Location 178
6.3 Polarization of Reader and Tag 182
6.3.1 UHF RFID Tags 182
6.3.2 Buddhist Cross-Shaped RFID Tag 184
6.4 Radiation of Circular Polarization from Patch
Antenna 185
6.4.1 Simulation Model of a Circularly Polarized Patch
Antenna 186
6.4.2 Right-Handed and Left-Handed Polarization 186
6.5 Prediction of Communication Distance 187
6.5.1 Communication Distance of UHF RFID Tags 188
7 Determination of Antenna Characteristics by Using
EM Simulators 191
7.1 Radiation Efficiency of Antennas 191
7.1.1 Definition of Radiation Efficiency 191
7.1.2 Measuring Radiation Efficiency 192
7.1.3 A Method for Calculating Efficiency Using EM
Simulators 194
7.1.4 Radiation Efficiency of Patch Antennas 196
7.2 Antenna Gain 199
7.2.1 Definition of Antenna Gain 200
7.2.2 What Is the Actual Gain? 202
7.2.3 Measuring the Antenna Gain 203
7.2.4 Does Higher Gain Mean Higher Performance? 204
7.2.5 How a Reflector Influences Directivity 206
7.2.6 Standing Waves Between Two Metal Walls 208
7.2.7 Magnetic Current Antennas 209
7.3 Bandwidth of Antennas 209
7.3.1 Definition of the Bandwidth 209
7.3.2 Design of a Wideband Dipole Antenna 211
x Introduction to Antenna Analysis Using EM Simulators
7.3.3 A Wideband Patch Antenna 213
7.3.4 Wideband Double Patch 215
7.3.5 Parallel Configuration of Patch Antennas 218
7.3.6 Wideband Short-Circuit Patch Antenna 222
7.4 Interrelation of Three Parameters 226
7.4.1 Small Antennas and Three Parameters 226
8 Practical Antennas 227
8.1 Ultrawideband Antennas 227
8.1.1 What Is a Pulse Excitation? 227
8.1.2 Log-Periodic Antennas 229
8.1.3 Design Example of a Log-Periodic Antenna 230
8.1.4 Self-Complementary Antennas 231
8.1.5 Unbalanced Half-Trapezoid Dipole Antenna 234
8.2 Receiving Antennas for Digital Terrestrial Television 239
8.2.1 Dipole Antenna with Mesh Elements 239
8.2.2 An Embedded Antenna for Receiving Digital
Terrestrial Television 241
8.3 Antennas for Cellular Phones 244
8.3.1 Meander Line Monopole Antenna 244
8.3.2 Meander Line Monopole Antenna with Ground
Conductor 245
8.3.3 Influence of Surrounding Metal Objects 250
8.3.4 Influence of Surrounding Dielectric Objects 250
8.3.5 Design of Matching Circuits 252
8.4 Small Antennas for Integrated Circuit Cards 256
8.4.1 Input Impedance of Integrated Circuits 256
8.4.2 Matching Method for IC Including Reactance 257
8.4.3 Changing the Shape of Dipole Elements to Achieve
a Match 258
8.5 The Wireless World Is Expanding 261
8.5.1 Small Embedded Antennas Have a Bright Future 261