Bandpass Filter Design based on Eighth-Mode SIW

This paper presents a two-layer fourth-order filter based on eighth-mode substrate integrated waveguide (EMSIW). . The filter consists of four EMSIW cavities, which are coupled through a fan-shaped window between the upper and lower layers. The filter adopts theTE101 mode. The filter has two transmission zeros on either side of the pass band, and delivers high frequency selectivity. Simulation results show that the central frequency of the filter is 3.52GHz, and the minimum insertion loss in-band is around 2.36 dB. The miniaturization and integration of the filter can be better realized by using EMSIW.