Channel improvement for line-of-sight MIMO using dual-beam 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 a high radio frequency incurs a large propagation loss that contracts the service area, there is an increase in the probability that a line-of-sight (LOS) environment will emerge. There is significant degradation in terms of channel capacity in MIMO transmission in a LOS channel and this is a considerable problem. This paper describes the application of a dual-beam reflectarray to improve the channel capacity of MIMO transmission in a LOS channel. Computer simulation results for 4×4 MIMO show that a remarkable increase in the channel capacity is achieved when establishing a dual-beam reflectarray within the LOS channel, e.g., approximately 1.7 bps/Hz when using a single beam reflectarray and the increase becomes 5.4 bps/Hz when using the dual-beam reflectarray.