Filter Design Based On Substrate Integrated Waveguide And Defective Ground Structure

With the rapid development of electronic and communication systems toward high integration,miniaturization,low cost and high performance,there is a growing demand for miniaturized passive microwave devices with high performance,especially for the filter to separate of frequency of microwave signal.Therefore,the introduction of the Substrate Integrated Waveguide(SIW)structure becomes critical.SIW is a kind of structure which can realize the transmission characteristic of traditional metal waveguide on the dielectric substrate.It not only has the advantages of light weight,small volume,low radiation loss,high power capacity and high quality factor,which are shared with both microstrip line structure and rectangular waveguide structure,but also easy to realize the plane integration and processing.These advantages make SIW technology once proposed extensively researched by the a large number of scholars of this filed.The main work of this paper is to design a high-performance miniaturized filter with a combination of Defected Ground Structure(DGS)and SIW structure.Firstly,this paper introduces the basic theory of microwave filter design,such as the classification of microwave filter,the basic parameter index and the main design theory.The prototype of low-pass filter is the original model to design other filter,so this paper makes a detailed introduction and analysis.Secondly,this paper introduces the basic structure of SIW,and introduces the tapered SIW-microstrip progressive transition structure,and then because of the SIW metallization through itself can be seen as a passive periodic structure,and the slow wave characteristics and band-stop characteristics are analyzed in detail.Finally,the SIW structure is analyzed and the theoretical basis is provided for the design of SIW filter.Finally,this paper introduces several common DGS structure and proposes improved dumbbell DGS and asymmetric T-shaped DGS,and then discusses the equivalent circuit and transmission characteristics of these two DGS.On the basis of all the theories,this paper combines the SIW structure with high-pass transmission characteristics and DGS with low-pass transmission characteristics to design two high-performance miniaturized microwave filters,which are SIW-DGS bandpass filters and SIW-DGS dual-band bandpass filters...