The main challenge in development of antenna array is a mutual coupling between two adjacent antenna elements. In this paper, a mutual coupling reduction of an antenna array structure using uniplanar compact electromagnetic bandgap (UC-EBG) superstrate is proposed. The antenna array structure is developed based on aperture coupled antenna due to its ability to optimize antenna and feeding line separately. UC-EBG superstrate structure consists of UC-EBG unit cells and superstrate layer, than the simple aperture coupled antenna array, superstrate-based antenna array and antenna array using UC-EBG superstrate are compared. The performance of these three antenna structures are numerically compared in terms of reflection coefficient, bandwidth, mutual coupling, gain and radiation pattern. By using UC-EBG superstrate, we are not only achieve mutual coupling reduction, but also bandwidth enhancement.