HF-MIMO capacity improvements using compact antenna arrays

The feasibility of compact collocated antennas in HF-MIMO systems has been investigated and the results compared with large collocated arrays. The impact of ionospheric conditions on the envelope correlation and MIMO capacity were also analysed. The antenna decorrelation between the receive elements and the corresponding capacity of the system are a function of the type of antenna array used and the prevailing propagation conditions in the ionosphere. The role of antenna phase patterns in contributing to the resultant decorrelation is also studied using the NEC antenna modelling software.