W-band dual-band waveguide band-pass filter using dual-mode cavities

A W-band dual-band waveguide band-pass filter composed of two dual-mode (TE101 and TE201) cavities and four single-mode (TE101) ones is presented. This dual-band filter with each passband of fourth-order Chebyshev response is synthesised and designed with the centre frequencies 85.35 and 101.45 GHz, as well as the 3 dB fractional bandwidths of 5.3 and 2.1% by adopting the dual-mode resonators and the controllable coupling technique. The prototype is fabricated by the conventional computer numerical control milling technology easily. The measured results are very close to the simulations in full W-band.