Investigations On The Substrate Integrated Waveguide And Its Application In Filters

Recent advances in electronic and communication technology further the need for small, high performance and low cost microwave and millimeter wave systems. Due to the difficulty of realizing passive components with high quality factor (Q) in semiconductive materials, now it is impossible to integrate a microwave or millimeter wave system on chip (SOC). Recently, a new technology called substrate integrated waveguide (SIW) has been proposed and developed as an attractive for low-cost, high-Q, relatively high-power capacity, and high-density integration of microwave and millimeter wave components and sub-systems. Because the SIW is a newly arisen technique, many theoretical problems still remain unclear and its applications are still far from being completed.In this dissertation, essential propagation characteristics and applications in filters of SIW are investigated.A novel finite difference frequency domain (FDFD) algorithm with perfectly matched layer (PML) and Floquet's theorem for the analysis of SIW guided-wave problems is presented. In this scheme, the problem is converted into a generalized matrix eigenvalue problem and finally transformed to a standard matrix eigenvalue problem that can be solved with efficient subroutines available. This approach has been verified with experiment.FDFD method is applied to analyze the eigenvalue problems of SIW cavity. It is proved theoretically that the energy leakage from the via gaps can be neglected contrasting to the heat dissipation and a SIW cavity with high-Q can be obtained easily.And several kinds of SIW filters are designed and fabricated on standard printed circuit boards (PCB): the coplanar waveguide (CPW) coupled SIW-cavity filters, the direct coupled SIW-cavity filters, the folded SIW-cavity filters, the SIW microwave filters with the periodic cross-slot defected ground structures (DGS), the SIW microwave filters with the square-slot microstrip DGS, and the SIW microwave filters with high-impedance short-line element. The simulated and measured results are presented to demonstrate the promising performances of the proposed filters.