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

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

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

Thesis (M.Eng.)(Electronic)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references.

The growth of the mobile communication subscription is the main driver of the operators¡¦ revenues, before the appearance of 3G mobile communication service. As the penetration rate of mobile phones jumped over 100% in Taiwan, it¡¦s obvious that the life cycle of the GSM system has shifted to the mature stage, which all of the operators are under the pressure of low growth rate of voice service and declining ARPU rate due to the fierce price war in the market, and started to introduce 3G service. The 3G mobile communication technology offers users higher speed data communication, mobile commerce solutions, and multimedia services on the current 2G mobile communication basis. This has brought hope to mobile communication industry. In order to enhance the value-added services, operators must evolve its current role, which simply provide equipment and infrastructure service, to become a total solution provider that can integrate the whole industry value chain vertically. Therefore, this study mainly focuses on the 3G industry value chain and the competitive strategies. Moreover, this study will discuss global mobile communication development circumstances and the operation strategies of the worldwide leading players, in order to come up with appropriate managing tactics. Hopefully, the successful experience from successful companies can help Taiwan operators to understand more about the trend of global communication market strategies

In the development of the global telecommunication industry, the telecommunications market in China is very important for development and planning of Multinational Corporations¡¦ (MNCs) global overall arrangement. Thus, the main purpose of this research is to discover the trend of international telecommunications industry, especially mobile communication industry. In addition, discuss the position and importance of China¡¦s telecommunications market within the global market under the framework of international telecommunication market. Moreover, we have to further analyze the policy and planning of the China government. Furthermore, We have to discuss the strategies and cooperated cases of telecom operators and equipment manufacturers in China¡¦s telecommunication market. Besides, Understanding the considerations of China government¡¦s criteria and principle of opening 3G in mainland China¡¦s telecommunication market is also an important issue. Finally, we have to realize what kind of role that foreign telecom firms act in the development of the China¡¦s telecommunications market.

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