The patch antenna is a radiating element which radiates along the walls of edges. The size of the patch antennareduces by increasing the resonant frequency. The gain and bandwidth of single patch antenna is not sufficient for militaryapplications. For this purpose the patch array antenna is designed. In the present work a square patch antenna design atresonantfrequency 5GHzandits array analysis is presented.Array antennas haswideapplications in bothmilitary,wireless communications. The side lobe levels of linear and planar patch antenna array are - 13.5dB. This is not suggestiblefor trackingthe targets. In this present work the side lobe level are decreased in the patch array antenna by introducing the standardamplitude distribution and side lobe level is reduced from -13.5dB to -31.24dB. In this work raised cosine amplitudedistributionisusedto reduce side lobe levelupto-31.24dB