Dual-Mode Wideband Bandpass Filter using Single SIW Cavity with Perturbation Slot

This paper reports a wide passband filter based on a planar dual-mode substrate integrated waveguide (SIW) cavity with perturbation slot. The passband is created using $\mathrm{T}\mathrm{E}_{\mathrm{l}01}$ and TE
102
modes of the cavity. The resonant frequency of TE
102
mode is reduced by loading a slotline at the top metallic plane of the cavity, and it is combined with the resonant frequency of $\mathrm{T}\mathrm{E}_{\mathrm{l}01}$ mode to generate a passband characteristic. The passband bandwidth (BW) can be changed by altering the slot length. To validate the concept, a wideband filter using dual-mode SIW cavity is designed, constructed, and measured. The measurement results illustrate that the filter operating frequency is 12.9 GHz with a 1-dB absolute BW of 2.4 GHz.