| With the rapid development of wireless communication systems, the tendencies of electronic information systems are miniaturization, reliable, multifunctional and low-cost. Meanwhile, there are more and more urgent demands on high-performance and miniaturized microwave passive components for system in package (SiP) technology. Therefore, it is very important to develop synthesized method of passive components, resolve the contradiction between high performance and high density. This dissertation investigates substrate integrated waveguide (SIW) and other planar resonators. Furthermore, some kinds of bandpass filters, diplexers, and other passive components are developed based on them.The main academic contributions of this dissertation are as follows.(1) Based on the coupled resonator circuit model of narrow bandpass filter, we developed the expression of frequency-dependent mixed coupling coefficients. Then, we can obtain the synthesized S-parameters quickly from the frequency-dependent coupling matrix, and it has been implemented in microstrip filter designs.(2) Mixed cross coupling is introduced into SIW filter designs firstly, and it can be achieved by inter-digital slot-lines between SIW cavities. Then, quasi-elliptic function can be obtained in the third-order cross-coupled SIW filter. In the fourth-order topology, an additional transmission zero can be used to suppress the first spurious passband. To achieve miniaturization of such filters, we etched one co-planar waveguide (CPW) on the top metal layer of SIW cavities to realize mixed coupling, meanwhile, the CPW is taken as one resonator.(3) Microstrip resonators are introduced to SIW filter designs. Two open-loop resonators are used to realize mixed source-load coupling, then, four transmission zeros can be get in the third-order SIW filter. Based on this coupling scheme, we developed one SIW diplexer in LTCC successfully.(4) T-septum SIW (TSSIW) cavity is proposed firstly. In comparison with folded- and ridged-SIW structures, TSSIW has flexible width of T-septum and height of substrates. Transverse resonance method is used to analyze the cutoff frequencies of the fundamental and higher mode. Finally, a fourth-order TSSIW filter with quasi-elliptic function is realized successfully, and wider stopband characteristic can be obtained.(5) Two dual-band SIW filters are realized, which are based on folded SIWs and evanescent-mode coupling. Their center frequency ratio of the second to first passband can be adjusted randomly, the size of them are reduced significantly in comparison with conventional dual-band SIW filters.(6) Indirect source-load coupling can be achieved by a CPW structure etched on the top metal layer of the dual-mode SIW cavity. Then, better frequency selectivity is obtained. The CPW is taken as non-resonating node (NRN), whose resonant frequency is far away from center frequency.(7) Originated from conventional microstrip dual-mode resonator, we proposed a compact three-mode stepped impedance resonator. Then, elliptic response can be achieved in the three-mode filter. Folded T-type stubs are used to make the proposed filter more compact, and the filter has wide stopband.(8) The coupling principle between SIW cavity and microstrip resonator is investigated in detail. Compact SIW filters are achieved by introducing single- and dual-mode microstrip resonators into their implementations. Furthermore, one fourth-order coupling scheme is superimposed by two third-order ones, which has better frequency selectivity.(9) Utilizing complementarities between SIW cavity and defected ground structure (DGS) etched on the ground plane of SIW cavity, we presented a compact third-order SIW filter. Such kind of filter has just occupied area of one SIW cavity; better frequency selectivity and wide stopband are obtained simultaneously. All the samples are fabricated on the single-layered printed circuit board (PCB) and LTCC to validate our proposed works, their measured results agree well with the simulated ones.
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