A Dual-Band BPF with Controllable Center Frequencies and Bandwidths Using a Single SIW Cavity

A compact dual-band bandpass filter (BPF) with controllable center frequencies (CFs) and bandwidths based on only one single substrate integrated waveguide (SIW) cavity has been presented. The proposed structure consists mainly of a pair of T-shaped slots which are etched on the top metal layer of the SIW cavity. The modes generated by the slots and the perturbed TE101 and TE102 modes in the cavity are used to achieve dual-frequency response. By changing the width and spacing of the two slots, the desired CFs and bandwidths of the passbands can be tuned independently. A prototype dual-band BPF operating at 3.49 and 9.27 GHz is designed and fabricated to validate the design approach. Measured results agree well with the simulated ones in this work.