Effects of antenna matching on compact MIMO beamforming systems in frequency-selective fading channels

A complete MIMO beamforming system model with mutual coupling and matching network is proposed to cope with frequency-selective fading channels. The overall system transfer matrix is derived using Z-parameter method. The transmit and receive weight vectors are iteratively determined using a MIMO beamforming scheme. Performance of the MIMO system with various antenna matching methods is studied in numerical experiment. Simulation results show that input impedance match gives good performance compared with the optimum impedance which maximizes the capacity. MIMO system performance can be improved by properly selecting the matching impedance.