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Reconfigurable Antennas for Adaptive MIMO Communication Systems Reconfigurable Antennas for Adaptive MIMO Communication Systems A Thesis Submitted to the Faculty of Drexel University by Daniele Piazza in partial fulfillment of the requirements for the degree of Doctor of Philosophy June 2009 c 2009 Daniele Piazza. All Rights Reserved. ii Dedications To my family: thanks for your love and support during my studies iii Acknowledgments I would like to express my sincere thanks to Prof. Kapil R. Dandekar for his invaluable and unique guidance during my studies and for his support in preparing this thesis. I would like to thank Prof. Michele D'Amico who gave me the opportunity to continue my research studies at Politecnico di Milano. I am very grateful to all my colleagues and friends from the Drexel Wireless System Laboratory for their continuos collaboration on common research topics. Special thanks to my parents and my brother that have always been close to me and supported me with their continuos help, their patience and their love during my studies and my research. A big thank to my girlfriend Anita for supporting and encouraging me during these years and a special thank to all my friends that have been close to me in these years. iv Table of Contents List of Tables . xi List of Figures . xx Abstract . xxi 1 Introduction . 1 1.1 Antennas for MIMO systems . 3 1.2 Innovative aspects of this thesis . 6 1.3 Thesis outline . 11 2 Antenna diversity and reconfigurability . 14 2.1 Spatial, polarization and pattern diversity . 14 2.1.1 Spatial diversity . 15 2.1.2 Polarization diversity . 16 2.1.3 Pattern diversity . 17 2.2 Reconfigurable antennas . 18 2.2.1 Polarization reconfigurable antennas . 18 2.2.2 Pattern reconfigurable antennas . 21 2.2.3 Compound reconfigurable antennas . 26 2.3 Summary . 30 TABLE OF CONTENTS v 3 MIMO channel models and antenna correlation . 32 3.1 MIMO system . 32 3.2 MIMO channel modeling . 35 3.2.1 Deterministic channel model . 39 3.2.2 Stochastic channel model . 39 3.3 Summary . 42 4 Reconfigurable printed dipole array . 44 4.1 Design motivation . 44 4.2 Reconfigurable printed dipole array design . 45 4.3 Performance in clustered MIMO channel model . 56 4.4 Ray tracing simulation results . 60 4.5 Measurements results . 63 4.6 Summary . 70 5 Reconfigurable circular patch antennas . 71 5.1 Circular patch: pattern and polarization diversity . 72 5.2 Reconfigurable circular patch antennas . 74 5.2.1 Reconfigurable circular patch antenna for pattern diversity (RCPA-PD) 75 5.2.2 Reconfigurable circular patch antenna for pattern and polarization diversity (RCPA-PPD) . 81 5.3 Experimental setup and channel model . 87 5.4 RCPAs performance . 90 5.4.1 RCPAs at one and both ends of the communication link . 91 TABLE OF CONTENTS vi 5.4.2 RCPA configuration performance . 95 5.4.3 Narrowband vs broadband capacity . 99 5.5 Summary . 101 6 Configuration selection scheme for pattern RCPAs . 104 6.1 MIMO system with reconfigurable antennas . 105 6.2 Reconfigurable circular patch antennas . 109 6.3 RCPAs performance in clustered channel model . 113 6.3.1 Clustered channel model and RCPA spatial correlation . 114 6.3.2 Effect of RCPA spatial correlation on configuration selection . 116 6.3.3 Effect of average system SNR on configuration selection . 119 6.4 Selection algorithm . 121 6.5 Effect of pilot assisted estimation on the channel capacity and BER . 124 6.5.1 Ergodic channel capacity . 125 6.5.2 Bit error rate . 128 6.6 Summary . 131 7 Two port reconfigurable CRLH leaky wave antenna . 134 7.1 Generalities of leaky wave antennas . 135 7.2 CRLH leaky wave antennas . 137 7.3 Reconfigurable leaky wave antenna . 140 7.4 System model and experimental setup . 146 7.5 Experimental results . 152 TABLE OF CONTENTS vii 7.5.1 Channel capacity . 153 7.5.2 Power saving . 156 7.6 RLWA in different channel scenarios . 158 7.7 Summary . 160 8 Reconfigurable antennas in MIMO ad hoc networks . 162 8.1 Comparison of RCPA-PD with RPDA . 164 8.2 System model and notation . 165 8.3 Antenna configuration selection methods . 167 8.3.1 Centralized configuration selection technique . 167 8.3.2 Distributed configuration selection technique . 168 8.3.3 Single side reconfigurable antennas . 169 8.4 Data collection . 171 8.4.1 Measurement setup . 171 8.4.2 Simulation setup . 173 8.5 Results . 174 8.5.1 RCPA-PD . 175 8.5.2 RPDA . 178 8.5.3 Comparing RCPA-PD with RPDA . 179 8.5.4 Effect of the number of configurations . 182 8.5.5 Effect of correlation between the patterns . 183 8.6 Summary . 185 TABLE OF CONTENTS viii 9 Conclusions . 186 Appendix A: MIMO channel sounder . 191 Appendix B: Table of symbols . 194 Appendix C: Table of acronyms . 197 Bibliography . 197 Vita . 211 ix List of Tables 4.1 List of structural parameters of the reconfigurable printed dipole array (RPDA). 48 4.2 Spatial correlation between patterns generated at two different ports of the RPDA. 51 4.3 Spatial correlation between patterns generated at the same port of the RPDA. 51 4.4 Measured radiation efficiency of the RPDA. 53 4.5 Average measured percentage capacity improvement achievable with the RPDA with respect to the \short-short" configuration when used in a 2×2 MIMO OFDM system. 67 5.1 RCPA-PD structural parameters . 78 5.2 Spatial correlation between patterns generated at two different ports of the RCPA-PD. 80 5.3 Spatial correlation between patterns generated at the same port of the RCPA- PD......................................... 80 5.4 Measured radiation efficiency of the RCPA-PD . 81 5.5 RCPA-PPD structural parameters . 83 5.6 Spatial correlation between patterns generated at two different ports of the RCPA-PPD. 84 5.7 Spatial correlation between patterns generated at the same port of the RCPA- PPD. 85 5.8 Measured radiation efficiency of the RCPA-PPD. 86 LIST OF TABLES x 5.9 Percentage capacity improvement achievable for a probability of 50% when using the RCPA-PD and the RCPA-PPD with respect to a system that em- ployes circular patch antennas operating in \mode 3". Noise level v = 100 nW ......................................... 92 5.10 Average channel capacity with efficiency normalization for the RCPA-PPD and the RCPA-PD used at the receiver. Noise level v = 100 nW . 93 6.1 Spatial correlation between patterns generated at two different ports of the RCPA for the same configuration -r ^1;k;2;k . 111 6.2 Spatial correlation between patterns generated at the same port of the RCPA -r ^1;k;1;m ...................................... 111 6.3 RCPAs characteristics . 114 6.4 Relationship of angle spread to reciprocal condition number for SNR = 5dB 124 6.5 MIMO system configuration . 125 7.1 Unit cell structural paramters. 141 7.2 Bloch impedance. ..
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