Mutual coupling reduction and pattern error correction in a 5G beamforming linear array using CSRR

A four-element printed antenna array operating at 25 GHz frequency with complementary split ring resonator. (CSRR) has been proposed for beamforming applications. The CSRR elements has been used to suppress the mutual coupling in the proposed array. The existence of the CSRR configuration in antenna array, controls the unnecessary surface current flow between the array elements, thus the mutual coupling between array elements has been significantly reduced up to -55 dB. The effect of mutual coupling on the array radiation patterns has been studied in the presence and absence of CSRRs. The effectiveness of CSRR has been studied by steering the main beam as well as the nulls in different angles. By implementing the CSRR elements in array antenna, the distorted array patterns have been recovered and are presented. The proposed antenna array with the CSRR has the advantage of easy and low-cost fabrication and it offers excellent coupling suppression without changing the antenna profile. The commercially available simulation tools such as Matlab and Ansys HFSS have been used for array weights calculation and antenna design respectively. Finally, the fabricated prototype has been experimentally verified, and it shows that the analytical and computed results agree well with the measured results.