Dielectric Resonator Antennas

This book focuses on the understanding of the Cylindrical Dielectric Resonator Antennas (CDRA). The book introduces the fundamentals of DRA, CDRA, identifying the modes in a CDRA, excitation techniques and recent advancements pertaining to the research of the CDRAs. The latest trends in the field are discussed, including wide bandwidth of operation, high gain, modal stability, mode and impedance matching techniques, Circularly Polarized CDRAs, beam forming and MIMO applications for modern wireless systems. The experimental validation, testing, fabrication methods and machining to achieve cylindrical and its reformed shapes are also presented. Artech House Antennas and Propagation Library Dielectric Resonator Antennas 1 Contents 6 Acknowledgments 10 1 Introduction to Dielectric Resonator Antennas 12 1.1鈥僄enesis of Dielectric Materials as Radiators 12 1.2鈥僐DRAs and Their Modes 15 1.3鈥僀DRA and Its Modes 18 1.4鈥僅DRA and Its Modes 20 1.5鈥僂quilateral Triangular DRA and Its Modes 25 1.6鈥僀onclusion 29 References 29 2 DRA Bandwidth Enhancement Techniques 32 2.1鈥僔arious Feeding Methods 32 2.1.1鈥僀oaxial Probe Feed 33 2.1.2鈥僊icrostrip Feeding 44 2.1.3鈥傾perture or Slot Feeding 48 2.2鈥傿andwidth Enhanced by Stacking of Various Permittivity Layers 54 2.3鈥僊etallic Loading 59 2.4鈥僀ompact and Low-Profile Geometry 64 2.5鈥僃ractal- and Reform-Shaped Geometry 69 2.6鈥僀onclusion 75 References 76 3 DRA CP Techniques 84 3.1鈥僀ircular Polarization by the Single-Feed Technique 87 3.2鈥僀P by Multiple-Feeding Techniques 96 3.3鈥僀P by Geometry Modification Techniques 101 3.4鈥僀P by the Array Configuration Technique 109 3.5鈥僀P by Switchable Feeding Techniques 116 3.6鈥僀onclusion 121 References 121 4 DRA Gain-Enhancement Techniques 128 4.1鈥僄ain Enhancement by Loading a Metamaterial or Frequency-Selective Surface on a DRA 130 4.2鈥僄ain Enhanced by Metal Integration of the DRA 136 4.3鈥僄ain Enhanced by Higher-Order Modes 144 4.4鈥僂nhancing Gain with a Dielectric Resonator Array System 150 4.5鈥僂nhancing Gain by Stacking Various Materials 158 4.6鈥僀onclusion 163 References 163 5 Multiple-Input and Multiple-Output DRAs and Diversity Applications 168 5.1鈥僊IMO Antenna Characteristics and Attributes 169 5.1.1鈥僐eflection Coefficient (R) 169 5.1.2鈥僒ransmission Coefficient (t) 170 5.1.3鈥僂nvelope Correlation Coefficient 170 5.1.4鈥僀hannel Capacity Loss 171 5.1.5鈥僊ean Effective Gain 171 5.1.6鈥僒otal Active-Reflection Coefficient 172 5.2鈥僑ingle-DRA Element with Dual- or Multiple-Feeding Techniques for MIMO Applications 172 5.3鈥僁ual-DRA Elements with Dual- or Multiple-Feeding Techniques for MIMO Applications 176 5.4鈥僊ultiple DRA Elements with Multiple Feeds for MIMO Applications 180 5.5鈥僀onclusion 183 References 183 6 Fabrication, Experimental Setup, Measurement, and Practical Considerations 186 6.1鈥僁ielectric Material and Its Selection 186 6.2鈥僉imitations in Practical DRA Considerations 190 6.3鈥僃abrication Methods and Machines 191 6.4鈥僔arious Measurements of the DRA 196 6.4.1鈥僊easurement of the S-Parameter 198 6.4.2鈥僃ar-Field Measurement Setup 199 6.4.3鈥僄ain and Antenna Radiation Efficiency Measurements 200 6.4.4鈥僀P Measurements 201 6.5鈥僀onclusion 202 References 202 About the Authors 206 Index 208 Dielectric,resonator;,Resonator,antennas;,Propagation;,978-1-63081-870-8 Dielectric resonator,Resonator antennas,Propagation,978-1-63081-870-8 Dielectric Resonator Antennas Contents Acknowledgments 1 Introduction to Dielectric Resonator Antennas 1.1 Genesis of Dielectric Materials as Radiators 1.2 RDRAs and Their Modes 1.3 CDRA and Its Modes 1.4 HDRA and Its Modes 1.5 Equilateral Triangular DRA and Its Modes 1.6 Conclusion References 2 DRA Bandwidth Enhancement Techniques 2.1 Various Feeding Methods 2.1.1 Coaxial Probe Feed 2.1.2 Microstrip Feeding 2.1.3 Aperture or Slot Feeding 2.2 Bandwidth Enhanced by Stacking of Various Permittivity Layers 2.3 Metallic Loading 2.4 Compact and Low-Profile Geometry 2.5 Fractal- and Reform-Shaped Geometry 2.6 Conclusion References 3 DRA CP Techniques 3.1 Circular Polarization by the Single-Feed Technique 3.2 CP by Multiple-Feeding Techniques 3.3 CP by Geometry Modification Techniques 3.4 CP by the Array Configuration Technique 3.5 CP by Switchable Feeding Techniques 3.6 Conclusion References 4 DRA Gain-Enhancement Techniques 4.1 Gain Enhancement by Loading a Metamaterial or Frequency-Selective Surface on a DRA 4.2 Gain Enhanced by Metal Integration of the DRA 4.3 Gain Enhanced by Higher-Order Modes 4.4 Enhancing Gain with a Dielectric Resonator Array System 4.5 Enhancing Gain by Stacking Various Materials 4.6 Conclusion References 5 Multiple-Input and Multiple-Output DRAs and Diversity Applications 5.1 MIMO Antenna Characteristics and Attributes 5.1.1 Reflection Coefficient (R) 5.1.2 Transmission Coefficient (t) 5.1.3 Envelope Correlation Coefficient 5.1.4 Channel Capacity Loss 5.1.5 Mean Effective Gain 5.1.6 Total Active-Reflection Coefficient 5.2 Single-DRA Element with Dual- or Multiple-Feeding Techniques for MIMO Applications 5.3 Dual-DRA Elements with Dual- or Multiple-Feeding Techniques for MIMO Applications 5.4 Multiple DRA Elements with Multiple Feeds for MIMO Applications 5.5 Conclusion References 6 Fabrication, Experimental Setup, Measurement, and Practical Considerations 6.1 Dielectric Material and Its Selection 6.2 Limitations in Practical DRA Considerations 6.3 Fabrication Methods and Machines 6.4 Various Measurements of the DRA 6.4.1 Measurement of the S-Parameter 6.4.2 Far-Field Measurement Setup 6.4.3 Gain and Antenna Radiation Efficiency Measurements 6.4.4 CP Measurements 6.5 Conclusion References About the Authors Index