A 93 GHz Circumferential Waveguide Bandpass Filter with Broad Bandwidth and Low Loss

A new waveguide band-pass filter has been developed and realized for W-band. It differs significantly from traditional microwave filters at lower frequencies subsequent upon a very simple arrangement which is well-suited for milled splitblock waveguide design. The band-pass filter consists of a circumferential waveguide section with three rotationally symmetrical feeding arms. One of them includes a slide which shorts the waveguide ring and thus cuts it into two halves. Consequently, the layout represents two short- and one open-circuited resonance lines. A bandwidth of more than 10 per cent and an insertion loss of typically 1 dB have been measured at a center frequency of 93 GHz.