In this study, an ultra wide band (UWB) antenna which radiates at 3-15 GHz is designed. The designed antenna has an arrow shaped patch and a ground layer. The size of the antenna is 41x31 mm and it's easy to produce. Because it has a simple geometric structure. The RCS (radar cross section) of the designed antenna is reduced by modifying the physical structure. RCS of the antenna is reduced up to 25 dB. The proposed antenna is fabricated and the experimental results of the radiation performance are in a good agreement with the simulation results.