Design of a Split Ring Resonator Integrated Triple-Band Ridge SIW Bandpass Filter on Defected Ground Structure

This research aims to develop a triple-band bandpass filter using ridge substrate integrated waveguide (RSIW) technology with high transmission and rejection capabilities. The filter is realized by two metallic planes separated by a substrate, and rows of metallic vias are placed to connect the edges of the two metallic layers. A rectangular-shaped metallic ridge is inserted in the substrate horizontally. These multilayer structures are designed and analyzed in search of sharp multiband characteristics. To enhance the filter performance, split-ring resonators, and defected ground structure are introduced on the top and ground planes. The size of the proposed bandpass filter is 1.52λg × 1.52λg. The three passbands are from 10.51 GHz to 12.74 GHz with a bandwidth of 2.23 GHz, from 14.68 GHz to 15.96 GHz with a bandwidth of 1.28 GHz, and from 17.09 GHz to 18.88 GHz with a bandwidth of 1.79 GHz. Minimum insertion loss values for the three bands are 0.19 dB, 0.68 dB, and 0.63 dB, respectively, with return loss values below 11 dB. The proposed bandpass filter can play a significant role in X- and Ku-band wireless communication-based applications.