Antenna Theory and Applications

Hubregt J. Visser, imec-NL and Eindhoven University, The Netherlands Hubregt J. Visser received the M.Sc. degree in electrical engineering from Eindhoven University of Technology, The Netherlands, in 1989.Upon graduation he joined TNO Physics and Electronics Laboratory, The Hague, where he has participated in several projects concerning near-field antenna measurements, monolithic microwave integrated circuits design, and phased-array antenna design. From mid 1996 to mid 1997, he was stationed at the European Space Research and Technology Centre, RF Systems Division, Noordwijk, The Netherlands, where he worked on infinite waveguide array antenna modeling. In 2001 he joined TNO Science and Industry, Eindhoven, The Netherlands where he has been involved in antenna miniaturization and rectenna projects. In 2009 he joined imec-Netherlands where he is involved in wireless energy transfer research.

Preface ix Acknowledgements xi List of Abbreviations xiii 1 Introduction 1 1.1 The Early History of Antennas 1 1.2 Antennas and Electromagnetic Radiation 2 1.2.1 Electromagnetic Radiation 2 1.2.2 Short Wire Dipole Radiation 5 1.3 The Modern History of Antennas 6 1.4 Frequency Spectrum and Antenna Types 8 1.4.1 Dipole Antennas 8 1.4.2 Loop Antennas 9 1.4.3 Aperture Antennas 10 1.4.4 Reflector Antennas 10 1.4.5 Array Antennas 11 1.4.6 Modern Antennas 11 1.5 Organization of the Book 12 1.6 Problems 13 References 13 2 Antenna System-Level Performance Parameters 15 2.1 Radiation Pattern 15 2.1.1 Field Regions 16 2.1.2 Three-Dimensional Radiation Pattern 17 2.1.3 Planar Cuts 19 2.1.4 Power Patterns 22 2.1.5 Directivity and Gain 25 2.1.6 Antenna Beamwidth 28 2.2 Antenna Impedance and Bandwidth 29 2.3 Polarization 32 2.3.1 Elliptical Polarization 33 2.3.2 Circular Polarization 35 2.3.3 Linear Polarization 35 2.3.4 Axial Ratio 36 2.4 Antenna Effective Area and Vector Effective Length 38 2.4.1 Effective Area 38 2.4.2 Vector Effective Length 40 2.5 Radio Equation 41 2.6 Radar Equation 43 2.6.1 Radar Cross-Section 44 2.7 Problems 46 References 47 3 Vector Analysis 49 3.1 Addition and Subtraction 49 3.2 Products 50 3.2.1 Scalar Product or Dot Product 50 3.2.2 Vector Product or Cross Product 51 3.2.3 Triple Product 52 3.3 Differentiation 53 3.3.1 Gradient 54 3.3.2 Divergence 55 3.3.3 Curl 57 3.4 Problems 61 4 Radiated Fields 63 4.1 Maxwell Equations 63 4.2 Vector Potential 64 4.3 Far-Field Approximations 69 4.3.1 Magnetic Field 69 4.3.2 Electric Field 73 4.4 Reciprocity 75 4.4.1 Lorentz Reciprocity Theorem 75 4.4.2 Antenna Reciprocity 77 4.5 Problems 79 References 79 5 Dipole Antennas 81 5.1 Elementary Dipole 81 5.1.1 Radiation 82 5.1.2 Input Impedance 86 5.2 Non-Infinitesimal Dipole Antenna 87 5.2.1 Radiation 87 5.2.2 Input Impedance 96 5.3 Printed Monopole and Inverted-F Antennas 97 5.3.1 Application of Theory 98 5.3.2 Planar Monopole Antenna Design 99 5.3.3 Printed UWB Antenna Design 105 5.3.4 Miniature Monopole with Cable Current Suppression 113 5.3.5 Inverted-F Antenna Design 120 5.4 Problems 128 References 129 6 Loop Antennas 131 6.1 General Constant Current Loop 131 6.1.1 Radiation 132 6.1.2 Input Impedance 136 6.1.3 Small Loop Antenna 137 6.1.4 Comparison of Short Dipole and Small Loop Antenna 138 6.2 Printed Loop Antenna 139 6.2.1 Application of Theory 139 6.2.2 Design of a Printed Loop Antenna 143 6.3 Problems 149 References 152 7 Aperture Antennas 153 7.1 Magnetic Sources 154 7.2 Uniqueness Theorem 156 7.3 Equivalence Principle 158 7.4 Radiated Fields 160 7.5 Uniform Distribution in a Rectangular Aperture 161 7.6 Uniform Distribution in a Circular Aperture 166 7.7 Microstrip Antennas 170 7.7.1 Application of Theory 172 7.7.2 Design of a Linearly Polarized Microstrip Antenna 175 7.7.3 Design of a Circularly Polarized Microstrip Antenna 179 7.8 Problems 185 References 188 8 Array Antennas 189 8.1 A Linear Array of Non-Isotropic Point-Source Radiators 189 8.2 Array Factor 195 8.3 Side Lobes and Grating Lobes 195 8.3.1 Side-Lobe Level 196 8.3.2 Grating Lobes 196 8.4 Linear Phase Taper 197 8.5 Grating Lobes 202 8.6 Special Topics 203 8.6.1 Mutual Coupling 203 8.6.2 Antenna Diversity 212 8.6.3 Sequential Rotation and Phasing 213 8.7 Array Antenna Design 217 8.7.1 Theory 220 8.7.2 A Linear Microstrip Patch Array Antenna 221 8.8 Problems 229 References 230 Appendix A Effective Aperture and Directivity 231 Appendix B Vector Formulas 235 Appendix C Complex Analysis 237 C.1 Complex Numbers 237 C.2 Use of Complex Variables 240 Appendix D Physical Constants and Material Parameters 243 References 244 Appendix E Two-Port Network Parameters 245 Appendix F Transmission Line Theory 249 F.1 Distributed Parameters 249 F.2 Guided Waves 252 F.2.1 VSWR and Reflection Factor 254 F.2.2 Impedance and Relative Impedance 254 F.3 Input Impedance of a Transmission Line 255 F.4 Terminated Lossless Transmission Line 255 F.4.1 Matched Load 255 F.4.2 Short Circuit 256 F.4.3 Open Circuit 256 F.4.4 Imaginary Unit Termination 257 F.4.5 Real Termination 257 F.5 Quarter Wavelength Impedance Transformer 257 Appendix G Coplanar Waveguide (CPW) 259 References 260 Index 261