Impact of Antenna Coupling on 2 $\times$ 2 MIMO Communications

The impact of mutual coupling induced by two closely spaced minimum scattering antennas at the subscriber unit on 2 $\times$ 2 multiple-input multiple-output channels and communications is investigated. Both (de)correlation effects and variations of antenna gain resulting from coupling mechanisms are considered. Relationships between coupling and correlations/channel Frobenius norm are discussed, pointing out the role of the interelement spacing, the array orientation, and the richness of scattering. The analysis also yields useful insight into the influence of mutual coupling on capacity and system performance.