DESIGN AND REALIZATION OF THREE-POLE BAND- PASS FILTER WITH SPURIOUS RESPONSE SUPPRES- SION USING DEFECTED GROUND STRUCTURES

In this paper, a three-pole bandpass fllter (BPF) using a new defected ground structure (DGS) is discussed. The proposed DGS is incorporated in the ground plane under the feed lines and the coupled lines of a bandpass fllter to improve the performance of the fllter in both passband and stopband. The banpass fllter is designed with a center frequency of 1.8GHz and a bandwidth of 270MHz. The suppression of better than 20dB was achieved for frequencies between 2.2 and 5GHz. A prototype of BPF was fabricated and tested. Prototype measured data was in good agreement with simulation results.