Design of Narrow Band Pass Filter Using Open Loop Circular Resonator

The paper proposes a compact and planar narrow band bandpass filter. The filter structure is formed by using two concentric open loop circular resonators structure. The basic structure of open loop circular resonator is inside coupled to another open loop to have the required passband performance. The filter does not comprise of defected ground structure and via that makes the fabrication easy. The narrow band associated with center frequency at 5.76 GHz. The s-parameter characteristic performance shows. A passband with a minimum value of insertion loss .99 dB and maximum value of return loss 17.16 dB. The passband has good selectivity and rejection performance on its both sides. The upper stop band extended from 5.88 GHz. The design parameter shows a filter of small size that is 4.7 mm × 4.6 mm. The proposed filter is designed and simulated in Key sight ADS.