This paper explains the impact of electromagnetic band gap structures towards the improvement of gain of four element microstrip antenna array. The conventional four element microstrip antenna array is resonating at a fundamental frequency of 5.53 GHz. The gain and the mutual coupling values at the resonant frequency of 5.53 GHz are 6.81, -16.95, -14.22 and -17.30 dB respectively. The proposed antenna array with I-shape slot EBG structure in the ground plane and fractal patch EBG structure on the surface produces reduced mutual coupling of -38.42, -32.10 and -36.94 dB at 5.53 GHz. An enhanced gain of 9.42 dB is produced at 5.53 GHz. The proposed antenna array produces a virtual size reduction of 77.92% with sizable reduction in back lobe radiation. The dielectric substrate used is FR-4 glass epoxy with dielectric constant 4.2 and loss tangent 0.0245. The antenna arrays are designed using mentor graphics IE3D software and measured results are obtained using vector network analyzer.