Mutual Coupling Reduction of Mimo Antenna Using Metamaterial Absorber for 5G Base Stations

Abstract

In this paper, a high port-to-port isolation multiple inputs multiple outputs (MIMO) dual-polarized antenna which covering N41 band has been present in favor of 5G New Radio (5GNR) base stations. The mutual coupling is reduced by using an array of metamaterial absorber which is orthogonally introduced in center of two subarrays at a center frequency of 2.6 GHz. The 3 $\mathrm{x} \ 8$ antenna array where the closely inter-antenna spacing (center to center) of 68 mm $\mathrm{x} \ 55$ mm $\boldsymbol{(0.59\ \lambda_{0} \ \mathrm{x} \ 0.48\lambda_{0})}$ is proposed. An array of $12 \ \mathrm{x} \ 1$ unit cell of metamaterial absorber is utilized to enhance col - polarized isolation (S31) and cross - polarized isolation (S21). The measured results which correspond well with the simulated ones illustrate a satisfactory mutual coupling reduction, thus cross - polarized isolation $\vert \mathrm{S}_{21}\vert$ has improved from -19 dB to -26.8 dB and the col - polarized isolation $\vert \mathrm{S}_{31}\vert$ has enhanced from -16.8 dB to -25 dB comparing to the utilization of metallic wall.