Compact Triple-Band Waveguide Bandpass Filter Using Concentric Multiple Complementary Split Ring Resonators

Abstract

This paper presents a compact tri-band waveguide bandpass filter using concentric multiple complementary split ring resonators (CSRRs). Two symmetrical concentric multiple CSRRs are placed on the transverse plane of a standard WR-90 rectangular waveguide at 8.41[Formula: see text]mm distance to achieve dual-pole, tri-band response. The proposed filter has been simulated using Ansoft High Frequency Simulation Software (version 14). Based on the simulated result the filter has been fabricated and tested. The measured result shows a dual-pole, tri-band, bandpass response with passbands at 8.04–8.2675[Formula: see text]GHz, 9.45–9.84925[Formula: see text]GHz and 11.35–12.005[Formula: see text]GHz, which is in good agreement with the simulated responses. The total length of the filter is 10[Formula: see text]mm, which makes it compact and light weight. An approximate equivalent circuit of the filter also has been provided.