Defected Ground Structure for Characteristic Enhancement of CSRR-based Substrate Integrated Waveguide BPF

Defected ground structure (DGS) is frequently involved to improve the characteristic response of microwave devices. In this paper, investigation of DGS utilization for characteristic enhancement of substrate integrated waveguide (SIW) bandpass filter (BPF) composed of complimentary-split-ring-resonator (CSRR) is presented. The filter is deployed on an FR4 epoxy dielectric substrate with the thickness of 1.6mm and the dimension of 45mm x 40 mm. The BPF which is designed by two reversely arranged CSRR incorporated on the SIW conductor surface provides passband extension at higher frequency producing the bandwidth response around 9 GHz. However, the use of CSRR also provides some unsatisfactory response at high frequency region requiring for the enhancement. By involving DGS into the BPF, the characteristic response at high frequency region could be enhanced with the bandwidth response achieves up to 10% improved.