ABSTRACT In this article, a 2 × 2 microstrip array antenna integrated with FIN defected ground structure (DGS) is investigated, which is designed for 3.24 GHz band operation. The FIN-DGS has been etched from the ground plane in the H-plane direction between two contiguous elements in a symmetric manner. Therefore, it suppresses the cross-polarisation (XP) radiation in the antenna without affecting its co-polarisation (CP) radiation characteristics. A proposed antenna has been designed and experimentally verified and shows <35 dB XP (±50º) radiation around boresight of the radiating elements in the H-plane with 10.7 dBi gain. The variation of XP fields has been investigated using the modal field distribution. The designed antenna provides a wide range of applications in adaptive arrays and space antennas, where 3D coverage with decreased XP values is the primary constraint.