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The worldwide demand for personal communication system (PCS) devices is motivating the development of compact, high-performance antennas. It is also prompting a better understanding of the effects of the user and the mobile communication environment on the antenna performance. The objective of this dissertation is to add to the current knowledge in both areas. Using the Finite-Difference Time-Domain (FDTD) technique, a monopole antenna and a diversity antenna were modeled for PCS applications. Also, techniques were developed and applied to facilitate the accurate numerical analysis of PCS antennas and to investigate the electromagnetic interaction between PCS antennas and the mobile communication environment. A monopole antenna and a polarization diversity antenna (PDA) were investigated at frequencies near 900 MHz. Antenna performance was evaluated in terms of the far-field radiation patterns, the mean effective gain (MEG), the radiation efficiency and the specific absorption rate (SAR) of energy in the user's body. For the diversity antenna, the statistical independence of the two diversity branches was determined from the correlation coefficient. The antenna modeling incorporated the antenna, a cellular telephone handset, models of the user's head and hand, and a statistical model of the mobile environment. Two mobile environments, an urban outdoor environment and a suburban outdoor environment, were modeled. The results show that (i) changing the antenna configuration from the monopole antenna to the PDA significantly affects the antenna efficiency and SAR in the user’s body; (ii) the type of mobile communication environment chosen (urban or suburban) has a pronounced effect on the correlation coefficient of the PDA and on the MEGs of the PDA and the monopole antenna; (iii) in terms of the MEG, the PDA is more sensitive than the monopole antenna to the presence of the user’s body; and (iv) overall, the PDA performs better than the monopole antenna in terms of antenna efficiency, peak averaged SAR in the head, and MEG. The accurate FDTD modeling of wires is crucial to the FDTD analysis of PCS antennas, particularly as monopole antennas and other linear wire antennas are often used with PCS devices. A study of the FDTD modeling of thin wires is included in this dissertation. The accuracy of the wire models was determined by calculating the input impedance of a dipole antenna over a broad range of dipole radii and comparing with the results of a Method of Moments formulation. Two existing thin wire models were analyzed and found to be inaccurate for some purposes. This finding led to the development of a new model, which includes a special treatment of the field components at the wire ends and a model of the source region. The proposed wire model is more accurate than the two existing wire models for a given spatial resolution. Thus, this new wire model facilitates accurate computations of input impedance and resonant frequency for linear wire antennas. The stability of the wire model was addressed, and a formulation for the maximum stability coefficient to be used with the proposed thin wire model was developed. / Graduate

A pattern-reconfigurable, low-profile, efficient, electrically small, near-field resonant parasitic (NFRP), Huygens source antenna is presented. The design incorporates both electric and magnetic NFRP elements. The electric ones are made reconfigurable by the inclusion of a set of p-i-n diodes. By arranging these electric and magnetic NFRP elements properly, a set of three Huygens sources are attained, each covering a 120 degrees sector. Pattern reconfigurability is obtained by switching the diodes on or off; it encompasses the entire 360 degrees azimuth range. A prototype was fabricated and tested. The numerical and experimental studies are in good agreement. The experimental results indicate that in each of its instantaneous states at f(0) = 1.564 GHz, the antenna provides uniform peak realized gains, front-toback ratios, and radiation efficiencies, respectively, as high as 3.55 dBi, 17.5 dB, and 84.9%, even though it is electrically small: ka = 0.92, and low profile: 0.05 lambda(0).

University of Macau / Faculty of Science and Technology. / Department of Electrical and Computer Engineering

by Hung Kwok Wah. / Summary in Chinese and English / Bibliography: leaves 43-46 / Thesis (M.Ph.)--Chinese University of Hong Kong, 1985

by Tam Wai Yip. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves [124]-[127] / ACKNOWLEDGEMENT --- p.i / LIST OF SYMBOLS --- p.ii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1-1 / Chapter CHAPTER 2 --- ANALYSIS OF MICROSTRIP ANTENNA ON A PLANAR SURFACE --- p.2-1 / Chapter 2.1 --- Dyadic Green's function formulation of a double-patch system --- p.2-3 / Chapter 2.1.1 --- Field components --- p.2-4 / Chapter 2.1.2 --- Boundary conditions and dyadic Green's function --- p.2-8 / Chapter 2.2 --- Microstrip antenna with an airgap --- p.2-14 / Chapter 2.3 --- Microstrip antenna with a superstate --- p.2-16 / Chapter 2.4 --- Galerkin's method --- p.2-18 / Chapter 2.5 --- Numerical computation --- p.2-25 / Chapter 2.6 --- Results and discussions --- p.2-30 / Chapter CHAPTER 3 --- ANALYSIS OF MICROSTRIP ANTENNA ON SPHERICAL SURFACE --- p.3-1 / Chapter 3.1 --- Fields in spherical coordinates --- p.3-3 / Chapter 3.1.1 --- solution of scalar Helmholtz equation in spherical coordinates --- p.3-3 / Chapter 3.1.2 --- Vector potentials --- p.3-6 / Chapter 3.2 --- Cavity model approach --- p.3-10 / Chapter 3.2.1 --- Formulation of radiation patterns --- p.3-11 / Chapter 3.2.2 --- Results and discussions --- p.3-23 / Chapter 3.3 --- Spectral domain approach --- p.3-39 / Chapter 3.3.1 --- General formulation --- p.3-39 / Chapter 3.3.2 --- Complex resonant frequency --- p.3-48 / Chapter 3.3.3 --- Far field radiation pattern --- p.3-51 / Chapter 3.3.4 --- Current distribution --- p.3-52 / Chapter 3.3.5 --- Limiting case of thin dielectric --- p.3-58 / Chapter 3.3.6 --- Results and discussions --- p.3-63 / Chapter CHAPTER 4 --- CONCLUSIONS --- p.4-1 / REFERENCES / Chapter APPENDIX I --- ASSOCIATED LEGENDRE FUNCTIONS / Chapter APPENDIX II --- SPHERICAL BESSEL FUNCTIONS / Chapter APPENDIX III --- VECTOR LEGENDRE SERIES / Chapter APPENDIX IV --- RESONANT FREQUENCY RELATION FOR THIN DIELECTRIC / Chapter APPENDIX V --- LIST OF PUBLICATIONS THAT ARE PRODUCED BY THE STUDIES

by Shu-chuen Lee. / "Revised : September 1994." / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 61-62). / Acknowledgment --- p.i / Lists of Illustration --- p.ii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- References --- p.4 / Chapter Chapter 2 --- The Meandering Inverted-F Antenna --- p.5 / Chapter 2.1 --- Evolution of the antenna --- p.6 / Chapter 2.2 --- The first prototype --- p.10 / Chapter 2.2.1 --- Geometry of the first prototype --- p.10 / Chapter 2.2.2 --- Resonant frequency --- p.12 / Chapter 2.2.3 --- Bandwidth --- p.16 / Chapter 2.3 --- Antenna with longer meandering line --- p.17 / Chapter 2.4 --- Antenna loaded with dielectric substrate --- p.20 / Chapter 2.4.1 --- Frequency characteristics --- p.21 / Chapter 2.4.2 --- Radiation pattern measurements --- p.22 / Chapter 2.4.3 --- Radiation patterns --- p.26 / Chapter 2.5 --- The 1.9GHz antenna --- p.34 / Chapter 2.6 --- Summary --- p.36 / Chapter 2.7 --- References --- p.37 / Chapter Chapter 3 --- The Meandering Posted Microstrip Antenna --- p.38 / Chapter 3.1 --- Introduction --- p.39 / Chapter 3.2 --- Theory --- p.40 / Chapter 3.3 --- Meandering Inverted-F antenna implemented on PCB --- p.44 / Chapter 3.3.1 --- Geometry for the antenna --- p.44 / Chapter 3.3.2 --- Microstrip bends --- p.45 / Chapter 3.3.3 --- Frequency characteristics --- p.47 / Chapter 3.3.4 --- Implementation of the microstrip antenna with different line width --- p.49 / Chapter 3.3.5 --- Radiation patterns --- p.51 / Chapter 3.4 --- Physical realization --- p.58 / Chapter 3.5 --- Summary --- p.60 / Chapter 3.6 --- References --- p.61 / Chapter Chapter 4 --- Conclusions --- p.63

by Tan Wai Pin. / Thesis (M.Phil)--Chinese University of Hong Kong, 1993. / Includes bibliographical references. / DEDICATION --- p.ii / ABSTRACT --- p.iii / ACKNOWLEDGMENTS --- p.ix / Chapter CHAPTER 1 --- p.10 / Chapter 1 --- INTRODUCTIONS --- p.10 / Chapter 2. --- REFERENCE --- p.15 / Chapter CHAPTER 2 --- COMPUTATION OF CYLINDER FUNCTIONS --- p.17 / Chapter 1. --- INTRODUCTION --- p.17 / Chapter 2. --- NEED OF COMPUTING CYLINDER FUNCTION OF COMPLEX ARGUMENTS --- p.18 / Chapter 3. --- NEED OF COMPUTING HANKEL FUNCTIONS --- p.19 / Chapter 4. --- OUTLINE OF APPROACH --- p.22 / Chapter 5. --- ALGORITHMS --- p.24 / Chapter 5.1. --- REGION 1: IM(Z) < 5 AND RE(Z)<16 : --- p.25 / Chapter 5.1.1. --- Computation of Jn(z) : --- p.25 / Chapter 5.1.2. --- Determination of Starting Index M: --- p.26 / Chapter 5.1.3. --- Determination of Normalization Constant : --- p.26 / Chapter 5.1.4. --- "Computation of Yn(z),Hn(1)(z) and Hn(2) (z)" --- p.29 / Chapter 5.2. --- REGION 2 : --- p.30 / Chapter 5.3. --- REGION 3 : --- p.32 / Chapter 5.3.1 --- Computation of Jn(z) : --- p.52 / Chapter 5.3.2 --- "Computation of Hn(1) (z),H(n2)(z) and Yn(z) :" --- p.40 / Chapter 5.3.3 --- Determination of Point of Starting Exponential Scaling : --- p.42 / Chapter 5.4. --- REGION 4 : --- p.42 / Chapter 5.5. --- REGION 5 : --- p.42 / Chapter 6. --- VERIFICATION --- p.43 / Chapter 7. --- REFERENCE --- p.46 / Chapter CHAPTER 3 --- INPUT IMPEDANCE OF CYLINDRICAL-RECTANGULAR MICROSTRIP ANTENNA --- p.48 / Chapter 1. --- INTRODUCTION --- p.48 / Chapter 2. --- FORMULATION --- p.49 / Chapter 3. --- DISCUSSION --- p.62 / Chapter 4. --- REFERENCES --- p.68 / Chapter CHAPTER 4 --- MUTUAL IMPEDANCE OF CYLINDRICAL-RECTANGULAR MICROSTRIP PATCH ANTENNAS --- p.70 / Chapter 1. --- INTRODUCTION --- p.70 / Chapter 2. --- FORMULATION --- p.70 / Chapter 3. --- DISCUSSION --- p.77 / Chapter 4. --- REFERENCES --- p.83 / Chapter CHAPTER 5 --- RESONANCE OF RECTANGULAR MICROSTRIP ANTENNA INSIDE A METALLIC CYLINDER --- p.84 / Chapter 1. --- INTRODUCTION --- p.84 / Chapter 2. --- FORMULATION --- p.85 / Chapter 3. --- NUMERICAL RESULTS --- p.96 / Chapter 4. --- CONCLUSION --- p.98 / Chapter 5. --- REFERENCES --- p.102 / Chapter CHAPTER 6 --- INPUT IMPEDANCE OF RECTANGULAR MICROSTRIP ANTENNA INSIDE A METALLIC CYLINDER --- p.104 / Chapter 1. --- INTRODUCTION --- p.104 / Chapter 2. --- FORMULATION --- p.104 / Chapter 3. --- NUMERICAL RESULTS --- p.106 / Chapter 4. --- CONCLUSION --- p.111 / Chapter 5. --- REFERENCES --- p.112 / Chapter CHAPTER 7 --- SUMMARY --- p.113 / APPENDIX A --- p.117 / APPENDIX B --- p.119 / PUBLICATION LIST : --- p.121

This thesis presents a new approach to the hardware test environment for a twist reflector monopulse antenna system with a radome extending current measurement practice. New research is presented on the optimisation of the design of a twist reflector monopulse antenna system with a radome, significantly improving the design and the design process. A unique extension to current measurement practice, for single channel antennas, is presented to determine the best practice method on phase stable measurements of a multi-channel antenna on a moving positioner. A novel axis transform for a 3 axis positioner system located within an anechoic chamber is derived. It allows for true performance measurement of a twist reflector antenna with a radome. This progresses the field of antenna measurement as, uniquely, this axis transform allows the aberration caused by the antenna radome to be measured and included. Design improvements have been made on polarisation selective grids, the matched thickness of the radome and a new software method that removes the need for a comparator and increases the robustness of the antenna system. Polarisation selective grids, constructed from a set of parallel conductors, have a wide range of uses in antenna systems. This thesis shows that the depth of a copper grid line can be reduced to 15 m and still provide better than -25 dB cross-polar isolation. This is contrary to current understanding at 30 times the skin depth. A new combined approach to radome thickness optimisation is presented that reduces the time taken to calculate the optimal thickness by over 3 orders of magnitude and the computer memory by over 2 orders of magnitude without compromising accuracy. The use of a digital comparator is described and leads to a novel method to compensate for a failed feed element, verifified in both simulation and anechoic chamber measurements.

In this thesis, two types of handset antenna design respectively for dual-band GSM850/1900 operation and seven¡Vband LTE/WWAN operation are presented. The proposed antennas can achieve decreased antenna size and enhanced operating bandwidth by shaping the system ground plane of the handset. The seven-band LTE/WWAN antenna is printed on the system circuit board with good radiation characteristics and occupies a small size of 24.5 x 10 mm2. At first, we propose a half-loop antenna structure which integrates its facing edge of the system ground plane as the resonant path of the antenna. In this case, the required length of the half-loop antenna structure is only about a half compared with the traditional loop antenna. Next, to enhance the operating bandwidth of the antenna, a parasitic shorted monopole strip is added and a shaped system circuit board is used. The shaped system circuit board can integrate the battery with the circuit board to help reduce the thickness of handset. Also, much enhanced operating bandwidth for the lower band can be obtained, owing to the enhanced surface current excitation in the system ground plane resulting from properly shaping the system circuit board. Effects of the user¡¦s head and hand on the proposed antenna are studied, and the simulated SAR and HAC results are also analyzed for bio-compatibility issue.