DGS (Defected ground structure) unified with square patch antenna is inspected using uniformity and non-uniformity structure. In this study, without affecting the dominant mode, input impedance and copol an air gap analysis between patch and defect in the ground plane has done to suppress cross polarization (X-pol.). The resonant frequency is 3.1GHz and X-pol. is suppressed approximately up to-13dB by increasing the gap of defect. © 2017 IEEE.