Key Technologies Of Miniaturize Passive Components Based On Substrate Integrated Waveguide

At the rapid development of information technology era,more and more stringent requirements for microwave devices has been made.rectangular waveguide cannot be integrated in the plane circuit because of its large volume.As a new transmission line,the substrate integrated waveguide(SIW)has good transmission characteristics,high quality factor and low loss,these merits make it replace the rectangular waveguide in many ways.More importantly,its special structure is easy to integrate in the flat circuit and SIW has the smaller size.At present,there are a lot of SIW-based microwave devices have come out and put into various fields for application,SIW technology is developing well.However,SIW technology is still difficult to achieve the level of miniaturization,which has become a bottleneck restricting the development of SIW technology.The purpose of this paper is to investigate the techniques of miniaturization and put them into the design of SIW to achieve miniaturization of SIW-based microwave devices.The paper mainly studies from the following aspects:1.The transmission theory of SIW has been introduced briefly.Based on the rectangular waveguide,the SIW model which are corresponded to rectangular waveguide has been established,and the transmission theory of SIW is analyzed.Several conversion structures used for integrating SIW and planar circuit are introduced.The miniaturization technology of SIW has been researched.Extensive study of miniaturization of microwave devices made the principle of miniaturization be understood,for the follow-up design to provide ideas and theoretical basis.2.A bandpass filter based on 1/8 mode and 1/16 mode substrate integrated waveguide.On the basis of SIW transmission theory and filter design theory,combined with miniaturization technology like EMSIW,1/16 mode SIW and CRME to designed resonant cavities to work at the negative frequency,and introduce coplanar waveguide to integrate with CRME creatively to achieve a good impedance matching,and get a wide out-of-band suppression.The resonant cavity implements two filters according to different topologies.The first is a 2-pole bandpass filter formed by combining two EMSIW resonators.The second is a trisection filter combined one EMSIW and two 1/16 mode cavities.They have achieved good performance.The miniaturization factor of 97.6% is achieved.3.A directional coupler based on HMSIW.On the basis of principle of coupler,a directional coupler based on HMSIW is presented.The slots for coupling is introduced and the influence of its number for S21 and S31 has been analyzed.The miniaturization factor of 89.47% is achieved.