A W-Band SIW Bandpass Filter with Controllable Transmission Zeros Using Perturbed Resonant Cavity

A novel substrate-integrated waveguide (SIW) cavity and its filter design are presented in this paper. The perturbed rectangular cavities can realize controllable transmission zeros (TZs). Four metalized vias are introduced symmetrical relative to the centerline, and the resonant frequency of TE 102 can pass through TE 301 mode, thus the movement and polarity reversal of TZ can be realized. A second-order filter with two perturbed cavities is proposed, and the simulation result shows that the filter achieves a low insertion loss and high out-of-band suppression with flexible controllable TZs.