The paper gives a detailed study of how to design a microstrip patch antenna array for UWB applications by using the FR-4 substrate material. The rectangular antenna array is designed with the planar ground. The designed antenna is a rectangular shape, compact and planar for the UWB applications. The size of the antenna is 20.50×15.22 mm (width and length), which resonated at a return loss – 14 dB, -31.23 dB and -33.36 dB and the input impedance is 50 ohms.