Control over passband bandwidth of dual mode bandpass filter based on compact Substrate Integrated Waveguide

A method to control the passband of dual mode bandpass filter based on compact substrate integrated waveguide (SIW) is presented in this paper. A miniaturized SIW cavity is sliced out from conventional circular SIW cavity. The bandwidth of generated passband which is based on higher order excited dual modes of this compact SIW cavity is controlled separately at both lower and upper sidebands. The fundamental mode (TM101) of the derived cavity is controlled by a perturbation via. TM102 and TM201 modes are employed to generate the filter passband. Along with the perturbation via a pair of slot lines with ‘V’ shaped configuration is loaded into the compact SIW cavity to control the intermodal couplings and govern the passband bandwidth. An 18.5% change in fractional bandwidth (FBW) by shifting the lower sideband and 4% change in FBW by shifting the upper sideband is established in this process. Minimum insertion loss suffered by the passband during the process of bandwidth control is within 1.5 dB.