A multiple-input multiple-output antenna with metamaterial enhancement for 5G channel sounding in the upper 6 GHz band

Abstract

This paper presents a compact 2 × 2 multiple-input multiple-output antena system designed for 5G smartphones operating in the upper 6 GHz band, and which is to be initially considered as a prototype resembling a user terminal in a channel sounding system. The antenna incorporates a split-ring resonator metamaterial layer, enhancing its gain by at least 1.5 dB across the entire bandwidth without increasing the size of the antenna. The results show a good agreement between the simulations and measurements, achieving a strong isolation, below −18 dB; a low envelope correlation coefficient, lower than 0.025; as well as an efficiency exceeding 75%, making it highly suitable for 5G Wireless applications, including both indoor as well as outdoor wireless channel characterization.