Performance Comparison of $2 \times 2$ MIMO Antenna Arrays With Different Configurations and Polarizations in Reverberation Chamber at Millimeter-Waveband

A performance comparison of 2 × 2 multiple-input multiple-output (MIMO) antenna arrays with different configurations and polarizations in a reverberation chamber (RC) is presented at the 28-GHz band. Eight types of antenna arrays are proposed according to different configurations and polarizations. The measured results of the antenna arrays show that they have similar antenna performance with respect to the same array size except for those concerning with the polarization. Based on these antenna arrays, we propose twelve cases of 2×2 MIMO antenna arrays with dual-separated polarizations between top and bottom side. A 28-GHz channel sounder and a vector network analyzer were used to measure complex channel transfer functions at the specific position of the rotating mode stirrer in the RC. The proposed MIMO antenna arrays were measured in the RC without and with absorbers. To clarify the channel performance for each case, a wideband channel capacity is calculated from the measured result.