Compact Substrate Integrated Waveguide Multiband Band Pass Filter using Octagonal Complementary Split Ring Resonators

Transmission line structure based on substrate integrated waveguide (SIW) loaded with new structure of octagonal complementary split ring resonator (CSRR) has been proposed. The SIW loaded CSRR pair is used in dual/quad octagonal structure to design dual band pass filter (single and double pole) with improved performance characteristics. The proposed band pass filter (BPF) yields two passbands (3.824.39) GHz (566 MHz) and (6.18-6.31) GHz (123MHz) with center frequency at 3.97 GHz and 6.2 GHz respectively. The simulated results are in good agreement with measured result. The results obtained by proposed filter are compared with others as reported in literature. It can be seen that the performance parameters such as bandwidth and insertion loss are improved by 14.27%, 0.7dB in first pass band and 2%, 2 dB in a second pass band respectively with transmission zero 5.57 GHz at stopband. The proposed filter structure leads to chronological minimization in size, low cost and quality factor obtained is 153. The proposed filter can be used in Cband of microwave link and easily integrated with other circuits.