Channel capacity of multi-antenna communication systems with closely spaced antenna elements

In this paper we analyze the causes and effects of mutual coupling on MIMO channel capacity. Mutual coupling not only affects the signal through correlation but also the thermal noise-a critical factor omitted from previous work. We study a two-antenna array by applying the Nyquist´s thermal noise theorem. Simulation results shows that mean MIMO channel capacity is underestimated if the noise correlation due to mutual coupling effect is not accounted for. We present results for both cases when the transmitter does and does not know the channel realizations