Design of Dual-Band Bandpass Filter Based on Substrate Integrated Waveguide Structure

This paper presents a novel dual-band bandpass filter design based on hybrid structure of substrate integrated waveguide (SIW) and complementary split ring resonator (CSRR). SIW is a novel structure with the combination of rectangular waveguide and microstrip transmission line. CSRR capacitive gaps are etched on the metallic surface to form a resonant cell. By combining SIW with CSRR structure, a dual-band bandpass filter has been designed and fabricated. The center frequencies of the filter are 2.4GHz and 3.5GHz, the maximum passband insertion loss is 0.5dB and the return loss is larger than 25dB. Transmission zeros appear at 3GHz, 4GHz and 5GHz, respectively, which make the band rejection larger than 40dB. Good agreements between the simulation and the experimental results are observed