A compact single feed rectangular microstrip patch antenna using dielectric substrate 4.2, loss tangent .0012 and having substrate height of 1.6 is used. The compact antenna of dimension (14mm X 18.6mm X 1.6mm) is used and analyzed on MoM based simulating software IE3D. A probe of different radius has been taken to improve the Bandwidth of the proposed structure. Simulation results show that antenna can realize wide band characteristics and single band of 4.148 GHz (impedance bandwidth of 76.53%) has been achieved.