Substrate-integrated waveguide triple-band filter with improved frequency and bandwidth allocations

Abstract

Substrate-integrated waveguide triple-band bandpass filter composed of two dual-mode (TE101 and TE201) rectangular cavities coupled with two single-mode (TE101) ones is synthesised and designed based on dual-mode resonances and split-type dual-band symmetrical frequency response. By applying the dual-mode frequency and coupling controlling techniques, the centre frequencies and fractional bandwidths (FBWs) of the three passbands can be allocated more flexibly. An experimental prototype centred at 11.578, 12.468 and 14.985 GHz with respective FBWs of 2.21, 2.21 and 2.3% is synthesised, designed, fabricated and measured for demonstration, showing good agreement between the measured and simulation results.