Research And Design Of SIW Filter And Duplexer Based On Multimode Technology

Microwave filters and duplexers play an important role in frequency selection in the field of wireless communication and have broad application scenarios.This thesis takes the substrateintegrated waveguide(SIW)as the main research body.Taking advantage of the performance of the SIW,several novel filters and duplexers are designed with the coupling theory and dual-mode technology.They have the advantages of low cost,small size,high operating frequency,and high integration.The main research work of this paper can be summarized as:1.A low-loss self-sealing filter based on the mixed mode of closed Patch and folded SIW is proposed.First,metallized vias and slot lines are introduced into the folded QMSIW resonator and the closed Patch,respectively,so that the fundamental modes of different resonators are the same.Next,by adjusting the inductive coupling of suitable resonators,a narrowband filtering response is achieved.Further,the closed triangular Patch resonator is embedded in the folded HMSIW,which not only reduces the mode of the HMSIW,thereby reducing the size of the HMSIW,in addition,using the first two modes of the HMSIW and the first one of the closed Patch A miniaturized and low-loss third-order filter is constructed,and the frequency of the used HMSIW mode is reduced,while the high-order mode remains almost unchanged,thereby realizing the filter’s wide stop-band characteristics.2.A Patch-SIW high-isolation duplexer based on an embedded coupled-line isolation network is proposed.First,the embedded coupling line isolation network is designed comprehensively.In addition,the coupling line is realized by stripline.The filter responses of the two channels are realized by folded SIW resonators and closed patch resonances,so that the insertion loss of the structure is small,and the in-band isolation of the two channels reaches more than 36 d B.3.A high-isolation miniaturized duplexer based on an embedded coupled-line isolation network and HMSIW dual-mode resonance is proposed.The duplexer uses an embedded microstrip-based coupled transmission line as an isolation network.At the same time,the channel’s filter response is adjusted to high frequency and low frequency by using the method of slotting and metallized through holes to disturb the mode,thereby realizing the flexibility design of the channel response.Moreover,based on the method of minimum electric field feeding,the suppression of the high frequency mode outside the channel is realized,so that the characteristics of a wide stop band can be obtained.