Quadruple-mode wideband filter using slotted substrate integrated waveguide circular cavity

In this article, a way to design a quadruple-mode bandpass SIW filter with single circular cavity has been investigated. The proposed filter is implemented using slotting technology and has a simple and symmetrical structure. It focuses on the multiple-mode resonator (MMR) technology to miniaturize the overall size of a wide bandpass filter (BPF). Totally five metallic perturbation via and slots are introduced to shift the resonant modes. The insertion loss of the filter with the quadruple-mode SIW cavity resonator is around 1.1dB. The passband is 14.8 GHz to 17.8 GHz, and the measured return loss is lower than −18 dB.