Abstract: This article demonstrates the performance enhancement of a simple and low cost four element array antenna by loading the electromagnetic band gap (EBG) structure in the ground plane. The paper discusses the alleviation of mutual coupling between the array elements is also observed. The distance between the adjacent array elements is maintained as ?/4 at the design frequency of 6 GHz. Initially the conventional four element array antenna is designed. The modified array antenna shows improved performance in terms of miniaturization, bandwidth, mutual coupling and radiation properties. It is resonating at three frequencies and a virtual size reduction of 30.01% is obtained. The array antenna designed possesses directional radiation properties. Mentor Graphics IE3D simulation software is used to design the antennas and measured results are obtained using vector network analyzer.

Keywords: Array antenna, Bandwidth, Periodic structure, Surface waves.