Design of Bandpass filter using Complementary Split Ring Resonators

A compact Bandpass filter is designed in this paper using novel triple concentric complementary Split ring resonators. A microstrip transmission line-based filter is designed by employing gaps between the transmission line which initially stops most of the frequencies with high attenuation. The coupling between the gaps is done through complementary split-ring resonators placed below the gaps in the ground plane. The resonance effect of the CSRRs will allow a certain band of frequencies. The performance is further enhanced by placing via between transmission line and ground plane. This combination resulted in a bandpass filter with Fractional Bandwidth of 10%, centered at 3 GHz frequency. The insertion loss is 1.5 dB in the passband at the center frequency. The roll-off rate is 58.8 dB/GHz on the lower side and 67.8 dB/GHz on the upper side of the passband.