Performance Analysis of High Pass Filter and Band Pass Filter Using DGS

The performance of a high pass filter (HPF) and a band pass filter (BPF) with and without defected ground structure (DGS) was analyzed in this specific work. The Defected ground structure includes rectangular and circular etched shapes in ground plane. Calculation and comparison of the response of both filters was done separately. Parameters of the proposed configuration were calculated at the centre frequency of 1.5 GHz and also proposed designs were fabricated with dielectric constant of 4.4, loss tangent of 0.02 and substrate height of 1.6mm. Results were simulated using computer simulation technology software (CST) and fabricated structures tested on a spectrum analyzer. The undesired sidebands and fluctuations of response were reduced by using defected ground structure (DGS). Also the cut off point of the high pass filer is shifted to a higher frequency and an improvement in selectivity is achieved in the case of band pass filter (BPF).