Microstrip patch antennas are the most common form of printed antennas. They became very popular due to their low profile geometry, light weight and low cost. A Rectangular Microstrip Patch Antenna with probe feed and substrate used is Arlon AD260 has the relative permittivity of which is 2.6 is designed and simulated using high frequency structure simulator (HFSS). All the Parameters of this microsrip patch Antenna such as bandwidth, S parameter, Reflection loss and VSWR has been found and plotted. The main objective of this work is to consider the reactive loading effect on the patch and its effect towards the improvement of the antenna characteristics, particularly the radiation characteristics in principle plane (E and H) is examined. As per theoretical approach reactive loading creates either capacitive loading or inductive loading. Due to this effect the antenna performance may be degraded or enhanced in terms of efficiency, isolation, gain, impedance matching etc. The results of this designed antenna are compared with the existing Micro strip antenna.