Research Of Filter Based On Half Mode Substrate Integrated Waveguide

With the rapid development of the radar system and the communication system,the tendency of modem microwave and millimeter-wave communication systems is miniaturization,low-weight,reliable,multifunctional and low-cost.As an important part of microwave system,the filters with high-quality,low insertion loss and good frequency selectivity have caught greater attention from the world.The paper is mainly devoted to the multi-layer filter that is designed based on general Chebyshev filter design theory together with substrate integrated waveguide(SIW).The multilayer technology reduces the area of SIW filters dramatically.The multi-layer filter based on substrate integrated waveguide not only has high performance,but miniaturization,low-weight and low-cost.The design of HMSIW-fliter is based on the research of SIW-filter.By adding periodic photonic band-gap structure(PBG)and uniplanar PBG,the frequency response characteristics of reflecting stop-band and transmission band of the filter can be effectively changed.At the same time,on the basis of HMSIW filter,by loading Defected Ground Structure(DGS),different shapes are etched on the metal floor surface to make it have slow wave characteristics.DGS can realize the bandgap characteristic.Also,the filter can be designed through simple cell structure.The HMSIW filter can effectively reduce the area of the device.Also it can take the advantages of high quality factor and low insertion loss of the traditional waveguide filter,and realize the miniaturization and light weight of the filter.The main research work of the thesis is as follows:Firstly,the design and synthesis of filters are introduced in detail.By studying the coupling matrix of Chebyshev low-pass filter and classical cross-coupled filter,the coupling coefficients and external quality factors of each cavity of the filter are determined.By simplifying the coupling matrix,extracting the coupling coefficient and external quality factor,the structure characteristics and specific size of the filter are determined.Secondly,this paper studies the transmission characteristics of SIW/HMSIW and its conversion structure with microstrip line,which lays a foundation for the design of its filter.Then,according to the coupling topology of the filter and the design synthesis of the filter,the SIW-based single-layer and multi-layer filters are studied.Finally,on the basis of SIW filter and by loading PBG/DGS structure,this paper studies and designs a variety of band-pass filters based on HMSIW.Based on the research of HMSIW filter,through the design and synthesis of the filter and the loading of PBG/DGS structure,the characteristics of miniaturization,light weight and high performance of the filter are realized,which provides more new ideas and methods for the design of the filter.