Mutual coupling reduction in a linear two element patch array and its effect on theoretical MIMO capacity

In this paper we present a study on the potential benefit that mutual coupling reduction can have on MIMO capacity. A simple line fed microstrip patch array is designed on a relatively thick substrate and then compared with the same structure having three periods of mushroom EBG (electromagnetic band gap) elements in addition to variable offset superstrates. We found that bandwidth is increased from 65 MHz to 115 MHz and that the transmission coefficient is reduced from -23 dB to -33 dB. Subsequently array impedance matrices are derived and used in the calculation of theoretical MIMO capacity. The spatial correlation matrices are generated from zero order Bessel functions of the first kind and are also included in the model. Capacity results are obtained via Monte Carlo simulations.