Research Of Half Mode Substrate Intergrated Waveguide (Hmsiw) Bandpass Filter

Filters as one of the key passive components in microwave system, its performance play an important role in the part of the whole system. Substrate integrated waveguide(SIW) filters have merits as high Q factor, high power capability and low insertion loss just like the conventional metal waveguide. Meanwhile, its have the advantage of small size, low cost, easy fabrication and integration which are similar to microstrip, which has gained a lot of interest among researchers and wireless industries. Particularly, half mode substrate integrated waveguide(HMSIW) flitters not only keep the original performance of SIW filters, but also it has just one half of the SIW filters in size. Therefore, it is believed the HMSIW filters have very bright prospect applications in microwave and millimeter wave circuits. This dissertation investigates two new techniques of HMSIW and other planar structures systematically. Several kinds of bandpass filters are developed based on them with compact configurations and good performances. The main contents are concluded as follows:Firstly, the elementary principle of design on the SIW/HMSIW filters is systematically illustrated in this chapter. The structure of SIW and HMSIW, their propagation performance and the equivalence between SIW/HMSIW and rectangular waveguide are introduced. In addition, several resonator cavities are analyzed. Finally, coupling manners based on coplanar and different surface of SIW are investigated, which can give us some suggestion for design the HMSIW filters.Secondly, the transitions between SIW/HMSIW and microstrip line are presented and studied in detail. At first we have thoroughly studied both the coplanar transitions and the no-coplanar transitions on SIW-microstrip, then make a compare on their transmission. Based on the SIW transitions, we have also investigated the coplanar transitions and the no-coplanar transitions on HMSIW-microstrip, which give a reference for HMSIW filters input/output structure.Thirdly, according to the coupling matrix technology, several innovative single-layer and multi-layer HMSIW bandpass filters based on SIW are proposed. Based on cross coupling theory, to the author’s knowledge, the prototype of doublet and modified doublet HMSIW bandpass is designed by the author for the first time. The proposed filters can achieve one or two transmission zeros with compact size. Then, we design a multi-layer cross coupling HMSIW bandpass filter. The proposed filter has properties of small size, high integration and good frequency selectivity, which verify the feasibility of HMSIW filters in multilayer LTCC structure.Finally, bandpass filters based on techniques of HMSIW and other planar structures are investigated in this dissertation. The characteristics of defect ground structure(DGS), split-ring resonator(SRR) and DGS SRR are analyzed and discussed. The design principles of bandpass filter based on HMSIW and Photonic Band-Gap(PBG), DGS are discussed respectively, and many HMSIW bandpass filter with wide band is proposed. Furthermore, several HMSIW bandpass filters load with SRR, DGS SRR and both of them are presented. The proposed filters are designed and fabricated, the measured results shows good agreement with simulated results, which validate the proposed filters. Filters in this paper exhibit the features with compact size, wide band and high selectivity.