Study On RF/Microwave High-Performance Miniaturized FIlters

Filters play important roles in many RF/microwave circuits. Emerging wireless communication applications continue to challenge RF/microwave filters with ever more stringent requirements-higher performance, smaller size, lighter weight, and lower cost. Based on the synthesis of cross-coupled resonator filters, a series of miniaturized planar filters have been proposed. These filters have low insertion loss, high stopband rejection, sharp selectivity, transmission zeros at certain frequencies, and first spurious response far away from the passband. It is believed that these proposed filters will find applications in the compact size and high-performance circuit design.In Chapter 1, the research background and recent developments about RF and microwave filters are reviewed.In Chapter 2, systematically research on the theory of generalized Chebyshev filters. The generalized Chebyshev filters are based on the all-coupled model. The coupling matrix, which can be physically realized, should be extracted. An optimization algorithm is presented for the extraction of coupling matrix of the generalized Chebyshev filters with direct source-load coupling and indirect source-load coupling. The coupling matrix of multiple-band bandpass filters are extracted with transmission zeros both in the passband and in the stopband.In Chapter 3, the dual/tripartite-mode resonators and bandpass filters are discussed. Fistly, proposed a novel center-stubbed dual-mode resonator. Based on the odd- and even-mode equivalent circuits, the resonance characteristics of the resonators are investigated. By introduce source/load coupling, different responses can be realized using only a single dual-mode resonator. A coupling and routing scheme is presented to model the operations of these filters. Secondly, proposed a novel center-stubbed tripartite-mode resonator. The field patterns of the tripartite modes and their mode splitting characteristics are investigated. The filter is very compact and has good stopband responses. In Chapter 4, the miniaturized scsresonators are investigated, and several innovative filter designs are proposed. Fistly, two high-low impedance loaded miniaturized resonators are presented and two four ordered cross coupling filter are designed. Secondly, the stepped-impedance CPW resonators are presented. The fundamental and first spurious resonant frequencies of the stepped-impedance CPW resonator are researched. A series of filter configurations, including the third-order Chebyshev and trisection bandpass filters are realized by the proposed resonators. These filters are very compact and have good stopband responses.In Chapter 5, firstly, a CSRR loaded Substrate Integrated Waveguide (SIW) filter is designed. Its take the advantages of low profile, low insertion loss, low interference etc. Secondly, CMRC loaded Substrate Integrated Waveguide filtersis are researched. Lastly, novel inductive post half-mode substrate integrate waveguide (HMSIW) filter is designed, which keeps the good performance of the SIW coupler with nearly a half reduction in size.In Chapter 6, a summary of the whole dissertation is given, and future research topics are suggested.