Parametric studies on effects of defected ground structure (DGS) for 6 GHz bandpass filter

Parallel coupled bandpass filter is proposed and designed by placing defected ground structure (DGS) in the ground plane. The proposed open loop dumbbell shaped DGS is used to tuned the bandpass filter to 6 GHz with a dimension of 50mm × 25mm. The bandpass filter is designed by using FR-4 printed circuit board and a tuning range of 0.994 GHz is achieved. This filter gives an insertion loss of -5.784 dB and a return loss of -11.051 dB. A comparison of the design of bandpass filter with open loop dumbbell shaped DGS is analyzed to identify the better performance of the bandpass filter. The results of simulated and measured filter is analyzed and discussed.