A Novel Approach for Capacity Improvement of 2x2 MIMO in LOS Channel Using Reflectarray

Multiple-input multiple-output (MIMO) transmission schemes with a high radio frequency are expected to make ultra high-rate mobile communications practical due to their high frequency utilization efficiency. On the other hand, since the high radio frequency incurs a large propagation loss that results in a contraction of the service area, there is an increase in the probability of a line-of-sight (LOS) environment. There is a significant degradation in terms of channel capacity in the MIMO transmission in a LOS channel and this is a considerable issue. This paper introduces a novel approach for improving the channel capacity of MIMO transmission in a LOS channel by employing a simple reflectarray within the LOS channel. We also perform an analysis of the eigenvalue and condition number for a 2 × 2 MIMO pure LOS channel matrix when using a reflectarray. The computer simulation results for the 2 × 2 LOS-MIMO channel show remarkable improvement in the condition number and the maximum increase of almost double the channel capacity when establishing one reflectarray within the LOS channel.