Low-cost Smart Antennas

Qi Luo, PhD, is a research fellow at the School of Engineering and Digital Arts, University of Kent, UK. He received his PhD degree in Electrical and Computer Engineering from the University of Porto, Portugal, in 2012. His areas of expertise include phased arrays, smart antennas, reflectarrays, circularly polarized antennas, MIMO and multiband antennas. He has authored and co-authored many papers in international journals and conferences. He is one of the authors of the book on Circularly Polarized Antennas (Wiley-IEEE, 2014). Steven (Shichang) Gao, PhD, is a Professor and Chair of RF and Microwave Engineering, School of Engineering and Digital Arts, University of Kent, UK. His research focuses on smart antennas, wideband/multi-band antennas, MIMO antenna systems and phased arrays. He co-authored and co-edited 2 books including Space Antenna Handbook (Wiley, 2012) and Circularly Polarized Antennas (Wiley-IEEE, 2014), over 300 refereed papers and 4 patents. He is an Associate Editor of IEEE Transactions on Antennas and Propagation and Radio Science, and was a Distinguished Lecturer of the IEEE Antennas and Propagation Society (2014-2016). He is the Director of Post-graduate Research at the University of Kent, UK. Wei Liu, PhD, is a Senior Lecturer at the Department of Electronic and Electrical Engineering, University of Sheffield, UK. He received his PhD from University of Southampton, UK. His research is focused on signal processing and its various applications, and in particular array signal processing (beamforming and direction of arrival estimation). He has published more than 250 journal and conference papers and a research monograph titled Wideband Beamforming: Concepts and Techniques (Wiley, 2010). He is an Associate Editor of IEEE Transactions on Signal Processing and IEEE Access and an editorial board member of Frontiers of Information Technology and Electronic Engineering. Chao Gu, PhD, is a Post-Doctoral Research Associate at the University of Kent, UK. His research focuses on smart antennas, reconfigurable antennas and THz antennas. He received his PhD from the University of Kent, UK. He has published several papers in IEEE Transactions on Antennas and Propagation on smart antennas and reconfigurable antennas.

• Preface ixAcknowledgement xiList of Abbreviations xiii1 Introduction to Smart Antennas 11.1 Introduction 11.2 Antenna Fundamentals 21.2.1 Antenna Impedance and Bandwidth 21.2.2 Radiation Patterns and Efficiency 41.2.3 Polarisations 81.3 Antenna Array Fundamentals 91.3.1 Array Performance Analysis 121.3.2 Active Reflection Coefficient and Mutual Coupling 121.3.3 Directivity and Beamwidth 141.3.4 Grating Lobe 151.3.5 Scan Blindness 161.4 Smart Antenna Architecture and Hardware Implementation 171.4.1 ADC and DAC 201.4.2 Digital Down-Converter (DDC) 201.4.3 Digital Signal Processor 201.4.4 Field-programmable Gate Array 211.5 Overview of the Book 22References 232 Beamforming Algorithms for Smart Antennas 252.1 Introduction 252.2 Basic Concepts for Beamforming 272.3 Fixed Beamformer Design 302.3.1 FIR Filter Based Design 302.3.2 Least Squares Based Design 322.3.3 Beam Steering 332.4 Adaptive Beamforming Algorithms 362.4.1 Reference Signal Based Beamformer 362.4.2 The Capon Beamformer 382.5 Blind Beamforming Algorithms 402.5.1 The Power Minimisation Algorithm 402.5.2 The Constant Modulus Algorithm 422.6 Low-cost Adaptive Beamforming 432.6.1 Analogue and Digital Hybrid Beamforming 432.6.2 Robust Adaptive Beamforming 452.7 Summary of the Chapter 50References 503 Electronically Steerable Parasitic Array 593.1 Introduction 593.2 Theory and Operation Principle 593.3 Low-cost Folded-monopole ESPAR 633.4 ESPAR Antenna with Low Control Voltage 703.4.1 FM-ESPAR using PIN diodes 703.4.2 Link Quality Test 723.5 Planar ESPAR Antennas 753.6 Case Studies 863.6.1 ESPAR using Monopole 863.6.2 Planar Ultra-thin ESPAR 903.7 Summary of the Chapter 98References 994 Beam-Reconfigurable Antennas Using Active Frequency Selective Surfaces 1034.1 Introduction 1034.2 FSS Fundamentals and Active FSSs 1044.2.1 FSS Elements 1044.2.2 Dielectric Loading Effects 1054.2.3 FSS Analysis Techniques 1064.2.4 Active Metal Strip FSS 1074.2.5 Active Slot FSS 1114.2.6 Active FSS Biasing Techniques 1134.3 Monopole-fed Beam-switching Antenna using AFSS 1144.4 Dual-Band Beam-Switching Antenna using AFSS 1204.5 3D Beam Coverage of Electronic Beam-Switching Antenna using FSS 1254.6 Frequency-agile Beam-switchable Antenna 1384.7 Continuous Beam-steering Antennas using FSSs 1454.8 Case Study 1534.9 Summary of the Chapter 159References 1605 Beam Reconfigurable Reflectarrays and Transmitarrays 1655.1 Introduction 1655.2 Reflectarray and Transmitarray Design Fundamentals 1665.2.1 Reflectarrays 1665.2.2 Transmitarrays 1695.3 Beam Reconfigurable Reflectarrays 1715.3.1 Multi-feed Reflectarray 1715.3.2 Reflectarray with RF Switches 1745.3.3 Reflectarray with Tunable Components 1775.4 Beam Reconfigurable Transmitarray 1815.5 Circularly Polarised Beam-steerable Reflectarrays and Transmitarrays 1855.6 Case Study 1895.7 Summary of the Chapter 195References 1966 Compact MIMO Antenna Systems 1996.1 Introduction 1996.2 MIMO Antennas 1996.2.1 Isolation 2006.2.2 Envelope Correlation Coefficient 2016.2.3 Total Active Reflection Coefficient 2026.3 Compact MIMO Antenna with High Isolation 2036.3.1 Neutralisation Technique 2036.3.2 Metamaterial 2056.3.3 Decoupling Network 2096.4 Compact MIMO Antenna with Adaptive Radiation Patterns 2156.5 Case Studies 2186.5.1 Increase the Physical Separation 2206.5.2 Change the Antenna Orientation 2206.5.3 Modify the Ground Plane 2226.5.4 Summary 2246.6 Summary of the Chapter 225References 2257 Other Types of Low-cost Smart Antennas 2297.1 Introduction 2297.2 Lens Antennas 2297.2.1 Lens Antenna Basics 2297.2.2 Millimetre-wave Lens Antenna Design 2317.3 Retrodirective Array Antenna 2367.3.1 Van Altta Array 2377.3.2 Phase Conjugating Array 2397.4 Fabry–Perot Resonator Antennas 2437.5 Array-fed Reflector 2467.5.1 Operation Principle 2467.5.2 Beam-switching Performance 2517.6 Multibeam Antennas based on BFN 2537.6.1 Butler Matrix 2537.6.2 Rotman Lens 2577.6.3 Blass and Nolen matrices 2597.7 Summary of the Chapter 261References 262Index 267