COMPACT LPF DESIGN WITH LOW CUTOFF FREQUENCY USING V- SHAPED DGS STRUCTURE

A class of compact microstrip Low Pass Filter (LPF ) with low 3dB cutoff frequency, ultrabroad stopband, and high stopband attenuation characteristics is introduced. It employs both shaped transmission line and Defected Ground Structure (DGS) techniques to achieve the aforementioned characteristics. In this paper, a new V-shaped DGS structure is introduced. The dimensions of the V-shaped DGS control the 3dB cuto ff frequency of the filter. On the basis of this study, different low pass filters having 3dB cutoff frequencies ranging from 1.2GHz to 1.688GHz are designed. A comparison with the low pass filter implemented using double U-shaped DGS structure having same substrate area is carried out.