A CPW fed two and four element antenna with reduced mutual coupling between the antenna elements for wireless applications

Mutual coupling between the multiple antenna designs is a critical problem which deteriorates the performance of multiple input multiple output (MIMO) system. It affects the antenna efficiency and influences the correlation. In this paper, a study on the isolation between the multiple antenna elements is presented. The antennas are placed on a cost-effective compact dielectric substrate with different orientations to minimize the correlation. A CPW fed antenna is designed using FR4 substrate, using which two and four element antenna structures are developed. The performance parameters are analysed, wherein the envelope correlation coefficient (ECC) has to be less than 0.5, diversity gain nearer to 10 dB in the operating bandwidth, mean effective gain (MEG) less than 3 dB, channel capacity loss (CCL) less than 0.4 bits/s/Hz and the isolation between the antenna elements well above 20 dB. Acceptable gain, high radiation efficiency, and stable radiation pattern of the proposed design are analysed and the fabricated prototype of two and four element is measured for its performance parameters. All the necessary simulations are carried out in the EM simulator Ansys HFSS v.14.0 and a detailed comparison study is done based on the existing antennas.