The MIMO systems are popular from the past two decades and more which is widely used in various wireless communications. It is clear from the theoretical point of view that the use of MIMO systems increases the capacity as compared to Single Input Single Output (SISO) and Single Input Multiple Output (SIMO) systems. This paper presents a dual band microstrip patch array antenna for both Multi-Input Multi-Output (MIMO) 4G Long-Term Evolution (LTE) and WiMAX application. The design, simulation and optimization processes are carried out with the aid of agilent ADS momentum technique. The designed array antenna operates at 2.2GHz and 3.6GHz bands for 4G LTE and WiMAX systems respectively.