Reduction of mutual coupling in antenna array using metamaterial surface absorber

Abstract

The reduction of direct coupling is an essential parameter in various MIMO and antenna array systems to minimize the interference between each element. In this article, the concept for reduction of mutual coupling between Vivaldi antenna arrays using metamaterial structure is proposed. The proof of concept for reduction of mutual coupling is presented using placement of metamaterial absorber at the intermediate distance between two directional end-fire antennas. The measured isolation between antennas with the aforementioned methodology is improved to 53.2 dB from 28 dB for the intermediate distance of 0.5λ0 between adjacent antennas. Further, the intermediate distance between the adjacent array elements is reduced to 0.25λ0 with an improved and acceptable mutual coupling of 37 dB. This will give the possibility to improve the resolution of an imaging array setup as the pixel size (distance between adjacent antennas) is getting reduced with decrease in separation distance between antennas.