A design of 300 GHz waveguide bandpass filter with H-plane offset inductive window

In this paper, a WR-2.8 band (220-325 GHz) waveguide bandpass filter is presented, and it is composed of five waveguide resonators. This improved directly coupled resonator filter with asymmetrical inductive windows is realized using H-plane offsets. The Chebyshev response filter has a centre frequency of 300 GHz, a fractional bandwidth of 4.6% and a passband return loss of 20 dB. Through the tolerance analysis, the micro-electromechanical systems(MEMS) and ultra-precision machining process with the precision within 5μm can be chosen for the filter fabricating.