Abstract. In this paper it has been described that electromagnetic band gap (EBG) structure design is applied in the antenna structure in order to enhance the performance of the antenna especially for improving the gain and radiation pattern. Microstrip patch antenna is used due to the advantages such as unchallenging and economically viable fabrication, light weight, low profile and can easily integrated with microwave circuit. This project involves the study of simulation results and fabrication process of EBG structure in the microstrip patch antenna using aperture coupled feeding technique . The simulation is done by using microwave Studio suite CST. From the simulation process, the designed microstrip EBG antenna shows considerable enhancement in performance in terms of radiation pattern, gain and return loss, S11 and works in the frequency range of 5.4GHz to 6.9GHz. Improvement in the mutual coupling is also shown in the designed aperture coupled microstrip EBG antenna and thus makes it suitable for wide angle scanning active phased array antenna. Other than that, the EBG structure also can be applied as a band reject especially for ultra wide band application which operates at very wide frequency ranges. By using aperture coupled microstrip EBG antenna of this design the overall gain performance is improved.