Abstract: Due to its small size, light weight, ease of integration, microstrip patch antenna is been widely applied to the fields of mobile radio, wireless communications, radar systems and so on. This paper presents a method of designing the millimeter-wave microstrip antenna which could be use in government and commercial applications, such as mobile radio and wireless communications that have similar specifications. The designed antenna can achieve triple band performance to simultaneously cover the 1.18GHz, 2.42GHz and 4.05GHz frequency with return loss of -12.50dB, -12.60dB and -15.50dB respectively. The simulation results of the designed triple band E-shaped Microstrip Patch Antenna were also presented. The antenna is of low profile, conformable to planar surfaces, simple and inexpensive to manufacture using modern printed-circuit technology. It was proved that the designed antenna is feasible and realizable. Because such antennas have a very low profile, are mechanically rugged and can be shaped to conform to the curving skin of a vehicle, they are often mounted on the exterior of aircraft and spacecraft, or are incorporated into mobile radio communications devices [1]-[5].