Dual bandpass filter based on hybrid spoof surface plasmon polariton and substrate integrated waveguide structure

A novel dual bandpass filter based on hybrid spoof surface plasmon polariton (SPP) and substrate integrated wave-guide (SIW) structure is proposed in this paper. In this design, H-shaped unite slots are etched on the top surface of SIW to form the spoof SPP. Thus, the surface wave mode of SPP can be excited and transmitted inside the closed structure of SIW. The dispersion and transmission characteristics of the proposed hybrid SIW-SPP transmission line (TL) are analyzed. Moreover, dual bandpass feature is observed in the proposed hybrid TL due to rejection introduced by capacitive-coupled series SPP.