Dual-Band SIW band-pass filter using circular CSRR and DGS

Abstract

This paper proposed a substrate-integrated- waveguide band-pass filter incorporating a circular complementary-split-ring-resonator co-etched with a defect-ground structure (DGS). Combining evanescent mode propagation and the TE101 fundamental mode yields a dual-band filter with center frequencies of 4.8 GHz and 9.7 GHz. The filter exhibits a fractional bandwidth (FBW) of 2.08 % and 60.61 % at -3 dB for the first and second bands respectively. Both bandwidths offer low insertion losses, measured at -0.87 dB and -0.85 dB. To improve out-of-band rejection, a pair of I-shaped DGS structures was integrated on either side of the CSRR. Electromagnetic analysis of the structure was performed using CST Microwave Studio simulation software.