Improvement of the LOS MIMO Channel Characteristic by Inserting a Directional Coupler Between the RF Transceivers and Antennas

In this paper, we proposed a novel approach to improve the MIMO channel characteristic by inserting a microwave directional coupler between the RF transceivers and antennas. Based on Ricean fading channel model, our research is focused on the characteristics of the channel matrix such as the condition number. Simulation results show that the LOS MIMO channel with the directional coupler is similar to that in the scattering environments without energy loss. Typical schemes are discussed with regard to different requirements. It could be a potential technique for high-speed data transmission in fixed broadband wireless access (BWA).