Spatial multiplexing of 4×4 UCA LoS MIMO systems with splitting matrix at RF band

LoS MIMO systems provide orthogonal channels when antennas are placed with appropriate configuration. However, in order to split the channels, a complicated RF network is necessary. Therefore, we propose a simple splitting matrix to solve this problem, which only includes four 90-degree hybrid couplers. By adopting it, a 4×4 UCA LoS MIMO system is achieved. The measured BERs and eye patterns validate that orthogonal channels are split, and a total data rate of 4Gbps is realized at 8GHz band. In addition, the system sensitivity to communication distance variation and antenna array orientation error is also investigated.