Research On High Performance And Compact Passive Components In Wireless Communication System

Research on high performance and compact passive components in wireless communication system has been done in this dissertation. Several schemes for high performance and compact passive component design are presented. Based on these schemes, some types of new passive components are designed. The work in this dissertation has an important value for the application of circuit design in wireless communication system.In Chapter 1, advances in the study of high performance and compact passive components in wireless communication system are introduced. At present, research on high performance and compact passive components is mainly developed from three aspects, i.e., new package technology, miniaturized resonator, and slow wave loading method. The research work in the three aspects is still at its beginning. There are many problems needed to be explored.In Chapter 2, microwave network theory related to the research in this dissertation is introduced. Two-port network theory corresponding to the filter design in Chapter 3, four-port network theory corresponding to the coupler design in Chapter 4, and one-port network theory corresponding to the filter antenna design in Chapter 5 are introduced.In Chapter 3, resonance property of stepped-impedance resonator is further analyzed with transmission line theory. Compact lowpass and bandpass filters are designed with the miniaturization property of stepped-impedance resonator. Tunable passband property of the stepped-impedance resonator is used for the design of dual-band bandpass filters that can be applied to wireless local network area communication system. Design theory for this type of filter is also presented. The proposed dual-band bandpass filter has the advantages of compact size, high performance, and simple structure.In Chapter 4, principle of coupler is analyzed by the even-odd-mode method. Circuit patterns designed by conventional method are introduced. The limitation of conventional design method is also illustrated. Based on the research progress of miniaturized coupler design, a novel tapered stepped-impedance slow-wave loading structure is proposed in this dissertation. With the combination of transmission line theory, microwave network theory, and equivalent circuit theory, an accurate equivalent circuit model is proposed and analyzed. High performance and miniaturized rat-race ring coupler, branch-line coupler, and dual-mode bandpass filter are designed with the proposed slow-wave loading structure. The proposed rat-race ring coupler's size is only 8% of conventional design at 1.44 GHz, and this is the best result reported up till now with printed circuit board manufacturing process. The proposed branch-line coupler not only effectively reduces the occupied area to 28% of the conventional branch-line coupler but also has high second harmonic suppression performance at 2.0 GHz. When the circuit area is kept the same, the proposed dual-mode filter has a better performance than the reported one, which has the smallest size in the literature.In Chapter 5, design theory for filter antenna with the second order and third order harmonic suppression is presented using the concept of microstrip resonator. Based on the concept of open end microstrip resonator, filter antenna with the suppression of the second order harmonic is designed. Filter antenna with the second and third harmonic suppression is designed by the use of both stepped-impedance resonator and open end microstrip resonator.In Chapter 6, the research work of this dissertation is summarized and potential research directions for high performance and compact passive components in wireless communication system are predicted.