OTA Experiments on Improved Angular Accuracy Reactively Loaded 32 × 32 MIMO/AOA Antenna

We are currently developing a 32 × 32 MIMO beam steering array, aiming at establishing an over-10 Gbps transmission rate. Angle of arrival (AOA) function is embedded into the array, enabling the radiation beam of the MIMO antenna to be directed precisely to incoming waves. There is a certain difficulty in terms of achieving the AOA antenna with a high accuracy because the AOA antenna is surrounded by a number of MIMO subarrays, which results in a strong electromagnetic mutual coupling. In this paper, an OTA experiment is carried out to confirm a method of reducing the EM coupling by means of controlling reactance loading. A significant reduction in the estimated error is confirmed by the reactance loading in a Rician propagation environment.