Study And Design Of SW-HNSIW Bandpass Filter

With the rapid development of wireless communication system in recent years,RF microwave circuit has increasingly higher demands on the miniaturization,multi-functions and high-integration.As one important part of RF microwave circuit,microwave filters have been one of research focuses.Combining the advantages of tranditional metal waveguide and microstrip,substrate integrated waveguide(SIW)has been widely applied in recent years.Based on SIW,a series of derived waveguides such as half mode substrate integrated waveguide(HMSIW),slow wave substrate integrated waveguide(SW-SIW)and slow wave half mode substrate integrated waveguide(SW-HMSIW)are put forward.In particular,SW-HMSIW shows great advantages when it is used to design filters,antennas,splitters and other active or passive devices,while maintaining high pass propagation characteristic and a much smaller size.Based on SW-SIW and HMSIW,SW-HMSIW is introduced in this paper.A dual-band filter based on SW-SIW and a compcact wideband filter based on SW-HMSIW are designed.This paper mainly includes the following parts:First,the transmission characteristics and design methods of SW-HMSIW are introduced on the basis of HMSIW and SW-SIW.Several conversion structures between SW-HMSIW and microstrip are designed.The electromagnetic simulation analyses of each conversion structure are carried out,and the merits and demerits of each conversion structure are compared.Then a smaller size of SW-SIW dual-band filter is designed in this paper,which is designed by etching two different sizes complementary split-ring resonators(CSRRs)on the upper surface of SW-SIW.The center frequency of each passband can be independently adjusted by changing the size of CSRRs.The design idea and implementation methods of such filter are detailed in this paper.Finally,a wide band filter using U-Slotted SW-HMSIW is designed.The influence of several key parameters on the filter is analyzed,which has great advantages compared with the tranditional filter.The measured results which show good agreement with the simulated results are provided,which verify the correctness of the design.