W-Band E-Plane Waveguide Bandpass Filter Based on Meander Ring Resonator

A $W$ -band $E$ -plane waveguide bandpass filter (BPF) is proposed using an embedded substrate with two metal strips and a meander ring resonator. The center frequency, bandwidth, and skirt selectivity of the proposed BPF can be easily adjusted. A simplified LC equivalent circuit is given to understand the operational mechanism of the BPF structure and investigate the distributions of the transmission zeros and poles. To validate the idea and show the performance of the designed $W$ -band BPF, a prototype example is manufactured and measured. The measurement results show that the waveguide BPF has a center frequency at 91.3 GHz with a bandwidth from 88.9 to 93.7 GHz, and the minimum insertion loss within the passband is 1.6 dB.