The Design And Research Of Reconfigurable Filter Based On Substrate Integrated Waveguide Technology

Filter is the basic component which is indispensable in wireless communication system and radar.Especially during the rapid development of the 5G communication,spectrum resource are getting tighter,thus,amounts of filters are needed on the system integration to meet the needs of spectrum requirements.As a new type of guided wave structure,Substrate Integrated Waveguide(Substrate Integrated Waveguide,SIW)is widely used in the design of microwave radio frequency circuit,for it has advantages of good thermal stability,large capacity of power,low dissipation,small volume and light weight,and easy to integrate.In order to solve the problem of filter space utilization in communication system.This paper is based on SIW and multiple plane structures and SIW reconfigurable filter is designed and implemented.It can reduce can decrease the usage quantity of filters,as well as save its space volume,and increase its utilization efficiency.First of all,this paper described the basic theory and equivalent model structure based on SIW,as well as several common SIW resonators and the transitional structure between the SIW resonator and the microstrip line.Then,this paper theoretically analyzed the structures of Split Ring Resonators(SRR),Spiral Resonator(SR),Complementary Split Ring Resonator(CSRR),Complementary Spiral Resonator(CSR),the Spurs line,the structure of the DMS,E microstrip line,and quadrature square patch resonator,and illustrated their advantages in the miniaturization of filters.Then,it also involved the introduction of the basic theories of varactor diode and PIN diode,equivalent circuit model and its main parameters in the design of SIW reconfigurable filter.Secondly,this paper designed and realized a reconfigurable filter which adopted the 1/2 structure SIW hexagon cavity,one half of the SIW hexagon cavity as the cavity,the rest of flank is used to design the bias circuit,resonant cavity loaded second-order complementary spiral resonator(CSR2),bias circuit loaded SMV1405 varactor,under the continuous adjustment of the bias circuit voltage,the filter's center frequency is adjustable continuously.Then,this paper designed and realized a dual-band bandpass electric tunable filter which adopted the structure of 1/4 SIW,using second-order complementary spiral resonator(CSR2),the spurs line and the structure of the DMS,and finally realized the reconfigurable filter which the center frequency of the first passband is adjustable continuously and the center frequency of the second passband is unchanged.Then,this paper based on the theory of HMSIW resonant cavity,load the second order complementary spiral resonators(CSR2),E microstrip line,between of them putted a bias circuit,connected through the SMV1345 PIN diode in the middle,and achieved a HMSIW dual-bandpass filter which can be switched.Finally,this paper designed and realized a switched filter which adopted the 1/4 SIW dual mode structure,cut off 3/4 of the SIW along the center line and get the 1/4 SIW,then uses the CSR2,SR3,orthogonal square patch resonators,SMV1345 PIN diode,and under the action of forward and reverse bias voltage,achieved the goal to switch between single and double passbands of filter.