Effect of antenna directivity on performance of multiple input multiple output systems in an underground gold mine

In this study two measurement campaigns are presented, where two types of multiple input multiple output (MIMO) antennas are investigated in an underground mine environment, aiming to identify the optimal antenna technology that allows to improve the performance of MIMO system in terms of root mean square (RMS) delay spread, path loss and capacity. It is found that in such scatter-rich environment, for line of sight scenario the directional antennas have provided significant suppression of multipath, giving a reduction in received RMS delay spread, and a corresponding increase in the correlation, which consequently decrease the channel capacity.