Adaptive Array Systems

Ben Allen completed his MSc and PhD degrees at the University of Bristol, U.K., in 1997 and 2001 respectively. Having undertaken post-doctorial research in the areas of smart antennas andMIMOwireless systems, he then became a lecturer at the Centre for Telecommunications Research, King's College London where he co-founded the UWB research group. He is now with the Department of Engineering Science, University of Oxford. He has published numerous journal and conference papers in the above areas as well as a book on smart antennas. He has been in receipt of the IEE J Langham Thomson Premium and the ARMMS Best Paper Award, both for publications relating to UWB. He is a senior member of the IEEE, chartered engineer, member of the IEE, and a member of the IEE's Professional Network Executive Committee on Antennas and Propagation. puter Science Contest, Pakistan, in 1998. He is a member of the IEEE and the IET, and serves on the UK Task Group on Mobile and Terrestrial Propagation.Mohammad Ghavami is Reader at the Centre for Telecommunications Research, King's College London. From 1998 to 2000 he was a JSPS Postdoctoral fellow in Yokohama National University, Japan, and from 2000 to 2002 he was a researcher at the Sony Computer Science Laboratories, Inc. in Tokyo, Japan.

• Preface xiAcknowledgments xvList of Figures xviiList of Tables xxixIntroduction xxxiiiI.1 Adaptive Filtering xxxiiiI.2 Historical Aspects xxxivI.3 Concept of Spatial Signal Processing xxxv1 Fundamentals of Array Signal Processing 11.1 Introduction 11.2 The Key to Transmission 21.2.1 Maxwell’s Equations 21.2.2 Interpretation 31.2.3 Key to Antennas 31.3 Hertzian Dipole 51.4 Antenna Parameters & Terminology 71.4.1 Polarisation 71.4.2 Power Density 71.4.3 Radiated Power 81.4.4 Radiation Resistance 91.4.5 Antenna Impedance 91.4.6 Equivalent Circuit 101.4.7 Antenna Matching 101.4.8 Effective Length and Area 101.4.9 Radiation Intensity 111.4.10 Radiation Pattern 111.4.11 Bandwidth 121.4.12 Directive Gain, Directivity, Power Gain 121.4.13 Radiation Efficiency 141.5 Basic Antenna Elements 141.5.1 Finite-Length Dipole 151.5.2 Mono-pole 171.5.3 Printed Antennas 171.5.4 Wideband Elements 181.5.5 Dual Polarised Elements 201.5.6 Sonar Sensors 211.6 Antenna Arrays 211.6.1 Linear Array 221.6.2 Circular Array 231.6.3 Planar Array 231.6.4 Conformal Arrays 241.7 Spatial Filtering 251.8 Adaptive Antenna Arrays 271.9 Mutual Coupling & Correlation 271.10 Chapter Summary 281.11 Problems 292 Narrowband Array Systems 312.1 Introduction 312.2 Adaptive Antenna Terminology 322.3 Beam Steering 352.3.1 Phase Weights 352.3.2 Main Beam Steering 362.3.3 Null Steering 382.4 Grating Lobes 412.5 Amplitude Weights 442.5.1 Window Functions 442.6 Chapter Summary 532.7 Problems 533 Wideband Array Processing 553.1 Introduction 553.2 Basic concepts 563.3 A Simple Delay-line Wideband Array 593.3.1 Angles of Grating Lobes 613.3.2 Beam Width 633.4 Rectangular Arrays as Wideband Beamformers 653.4.1 Rectangular Array Antenna in Azimuth 663.4.2 Beamforming using IDFT 693.4.3 Beamforming using Matrix Inversion 733.4.4 Numerical Examples 753.4.5 Summary of Wideband Frequency Selective Rectangular Arrays 823.5 Wideband Beamforming using FIR Filters 843.5.1 Continuous Linear Wideband Array 843.5.2 Beamformer Implementation 853.5.3 Sensor Locations 883.5.4 Design of Primary Filters 903.5.5 Design of Secondary Filters 923.5.6 Numerical Examples 923.6 Chapter Summary 933.7 Problems 944 Adaptive Arrays 974.1 Introduction 974.2 Spatial Covariance Matrix 984.3 Multi-beam Arrays 1004.4 Scanning Arrays 1004.5 Switched Beam Beamformers 1014.6 Fully Adaptive Beamformers 1044.6.1 Temporal Reference Beamforming 1064.6.2 Spatial Reference Beamforming 1074.7 Adaptive Algorithms 1084.7.1 Wiener Solution 1094.7.2 Method of Steepest-Descent 1114.7.3 Least-Mean-Squares Algorithm (LMS) 1124.7.4 Direct Matrix Inversion (DMI) Algorithm 1134.7.5 Recursive Least-Squares (RLS) Algorithm 1154.8 Source Location Techniques 1164.9 Fourier Method 1174.10 Capon’s Minimum Variance 1184.11 The MUSIC Algorithm 1184.12 ESPRIT 1214.12.1 Unitary ESPRIT 1224.13 Maximum Likelihood Techniques 1244.14 Spatial Smoothing 1254.14.1 Comparison of Spatial Parameter Estimation Techniques 1274.15 Determination of Number of Signal Sources 1274.16 Blind Beamforming 1294.16.1 Decoupled Iterative Least Squares Finite Alphabet Space-Time (DILFAST) Algorithm 1304.16.2 Spectral Self-Coherence Restoral (SCORE) Algorithm 1314.16.3 Constant Modulus Algorithm (CMA) 1324.16.4 Least-Squares Despread Respread Multitarget Constant Modulus Algorithm (LS-DRMTCMA) 1334.17 Chapter Summary 1334.18 Problems 1345 Practical Considerations 1355.1 Introduction 1355.2 Signal Processing Constraints 1365.2.1 Phase Error 1365.2.2 Element Position Error 1375.2.3 Element Failure 1375.2.4 Steering Vector Error 1375.2.5 Ill-Conditioned Signal Processing Matrices 1375.2.6 Weight Jitter 1385.3 Implementation Issues 1385.3.1 System Linearity 1455.3.2 Calibration 1465.3.3 Mutual Coupling 1545.3.4 Circular Arrays 1565.4 Radiowave Propagation 1605.4.1 Narrowband Single Antenna Channel Model 1615.4.2 Multiple Antenna Channel Model 1625.4.3 Wideband Multiple Antenna Channel Model 1635.4.4 Uplink-Downlink Channel Modelling for FDD Systems 1685.5 Transmit Beamforming 1705.5.1 Blind Techniques 1725.5.2 Feedback Based Techniques 1775.5.3 Switched Beam Techniques 1785.5.4 Downlink Signal Distribution Schemes 1795.6 Chapter Summary 1815.7 Problems 1816 Applications 1836.1 Introduction 1836.2 Antenna Arrays for Radar Applications 1836.3 Antenna Arrays for Sonar Applications 1846.4 Antenna Arrays for Biomedical Applications 1866.4.1 Medical Ultrasonic Arrays 1866.4.2 Space-Time Beamforming for Microwave Imaging 1926.5 Antenna Arrays for Wireless Communications 1936.5.1 Uplink Beamforming for Second-Generation Mobile Wireless Networks 1966.5.2 Downlink Beamforming for Third-Generation Mobile Wireless Networks 2076.5.3 User Location and Tracking 2196.5.4 Beamforming for Satellite Communications 2316.6 Chapter Summary 2356.7 Problems 236References 239Index 251