Substrate Integrated Waveguide Dual-Band and Wide-Stopband Bandpass Filters

In this letter, a new coupling structure implemented on a single-layer substrate and its application to design substrate integrated waveguide (SIW) dual-band and wide-stopband bandpass filters are presented. The TE101 and the TE102 modes of SIW cavity are used to design the proposed filters. By adjusting the dimensions of the coupling structure, the coupling coefficients of TE101 and TE102 modes can be controlled that can be used to design wide-stopband and dual-band bandpass filters. In the dual-band filter design, a slotline perturbation is used to lower the resonant frequency of TE102 mode while it has little effect on TE101 mode. To validate the proposed design approach, two SIW bandpass filters (wide-stopband and dual-band) are designed, fabricated, and measured.