Novel dual-mode substrate integrated waveguide (SIW) bandpass filter

In this paper, a novel dual-mode substrate integrated waveguide resonator which is a square SIW cavity perturbed by a rectangle metallic plane inserted into the middle of the substrate. With this type of dual-mode substrate integrated waveguide cavity, a novel fourth-order bandpass filter is presented. The filter was fabricated and measured with high selectivity and compact size, and the size reduction of less than 50% is achieved. The experimental filter exhibits a passband which is centered at 11.2GHz with an insertion loss of <0.5dB. The measured results are in good agreement with the simulated ones.