Dual-band Bandpass Filter Using Complementary Split Ring Resonators for X-Band Applications

This paper is focused on Complementary Split Ring Resonator (CSRR) to design a dual band bandpass filter (BPF) for X-Band frequencies using metamaterial concept. To achieve the functionalities of metamaterials, rectangular shaped complementary split ring resonators are etched in the ground plane along with λ /4 microstrip lines on the top. The inner and the outer rings are joined at the center through a gap. The length of the inner ring and the outer ring are calculated to make the BPF operating at 8.2 GHz and 9 GHz in X-Band. The width of the inter-connecting gap is changed to control the passband edges. An equivalent circuit model is proposed for the designed dual-band BPF to understand the working of the basic cell along with a microstrip line. By varying the length and width of the CSRR and changing the microstrip line dimensions two resonances are can be adjusted and finally fixed at our desired resonating frequencies. The results of EM simulation and the circuit simulation are compared to confirm the validity of the proposed design.