Design of Low Loss Dual-Mode Bandpass Filter Based on Printed Ridge Gap Waveguide

A dual-mode filter based on PRGW is proposed in this paper using stepped impedance resonator, which has a compact circuit size and strong design feasibility. In order to simplify the procedure of this design on PRGW, we separate the MS from the lower layer and verify the effectiveness of it, a transition from MS to PRGW is designed which also improves the stability of the air layer. By adjusting the size appropriately and introducing a suitable feeder, we increase the selectivity of the filter. The center frequency of the proposed filter is 32.625GHz and the relative bandwidth is 9%. It has low insertion loss(less than 0.3dB) due to the air layer.