Microstrip patch antennas have been widely used in a various useful applications, due to their low weight and low profile conformability, easy and cheap realization. In this paper, an attempt has been made to investigate new microstrip antenna structure for GSM 1800 band and WiMAX system applications. CST MWS and MATLAB software's are used for the simulation and design calculations of the microstrip antennas. The return loss, VSWR, directivity, gain and radiation pattern is evaluated. Using ST MWS simulation software proposed antenna is designed/simulated and optimized.