Differential Antennas

About the Author xiii

Preface xv

Acknowledgments xix

1 Introduction 1

1.1 Background 1

1.2 Balanced and Unbalanced Antennas 1

1.3 Even and Odd Modes 3

1.4 Differential and Single-Ended Circuits 4

1.5 An Important Ratio 5

1.6 Mixed-Mode S-Parameters 6

1.7 Balun 8

1.8 Concluding Remarks 11

2 Differential Wire Antennas 13

2.1 Introduction 13

2.2 Dipole and Monopole Antennas 13

2.3 Folded Dipole and Monopole Antennas 17

2.4 Loop and Half-Loop Antennas 20

2.5 Loop-Dipole and Half-Loop-Monopole Antennas 27

2.6 Yagi-Uda and Half-Yagi-Uda Antennas 33

2.7 Concluding Remarks 36

3 Differential Slot Antennas 39

3.1 Introduction 39

3.2 Slot and Half-Slot Antennas 40

3.3 Self-Complementary Antennas 44

3.4 Yin-Yang Antennas 45

3.5 Concluding Remarks 58

4 Differential Microstrip Patch Antennas 61

4.1 Introduction 61

4.2 Cavity Model 63

4.3 Rectangular Patch 72

4.4 Circular Patch 93

4.5 Stacked Patch 116

4.6 Patch Arrays 128

4.7 Applications 149

4.8 Concluding Remarks 151

5 Differential Microstrip Shorted Patch Antennas 161

5.1 Introduction 161

5.2 SPA and DSPA 162

5.3 Modified SPA and DSPA 178

5.4 PIFA and DPIFA 186

5.5 ME and DME Dipoles 197

5.6 Concluding Remarks 211

6 Differential Microstrip Slot Antennas 215

6.1 Introduction 215

6.2 Resonant Modes 215

6.3 Excitation of Resonant Modes 217

6.4 Half-Wavelength Microstrip Slot Antenna 222

6.5 Full-Wavelength Microstrip Slot Antenna 225

6.6 Concluding Remarks 228

7 Differential Microstrip Grid Array Antennas 231

7.1 Introduction 231

7.2 Basic Configuration 232

7.3 Principle of Operation 233

7.4 Fundamental Characteristics 234

7.5 Differential Excitation 236

7.6 Design Procedure, Formulas, and Examples 238

7.7 An Impedance Matching Technique 245

7.8 A Slow-Wave Structure 246

7.9 Dual Current Modes 252

7.10 Co-Aperture Dual Bands 253

7.11 Applications 257

7.12 Concluding Remarks 263

8 Differential Printed Antennas 267

8.1 Introduction 267

8.2 Quasi-Yagi Antennas 267

8.3 Fractal Antennas 287

8.4 Spiral Antennas 293

8.5 Applications 300

8.6 Concluding Remarks 303

9 Differential Antenna Measurements 307

9.1 Introduction 307

9.2 Impedance 307

9.3 Efficiency 318

9.4 Radiation Pattern 323

9.5 Gain 323

9.6 Concluding Remarks 326

References 327

Index 329