Near-Field Cross-Correlation Analysis for MIMO Wireless Communications

We propose a source-based approach to the analysis and evaluation of cross correlation in generic near-field (NF) interaction scenarios. The proposed theory integrates electromagnetics and stochastic considerations to derive a general formula for Rx port-to-port cross correlation. The derivation is quite general and is expressed in terms of the stochastic correlation tensor of arbitrary random NF source cloud close to the Rx multiple-input-multiple-output (MIMO) antenna terminals. The theory is then simplified by computing the response to a random NF point source, allowing fast and efficient computations when the NF source is replaced by an equivalent infinitesimal dipole model. The resulted formula is then exploited to devise a new cross-correlation performance evaluation metric suitable for the design of optimum NF spatial diversity applications antennas. The proposed approach and performance evaluation metric are anticipated to play a direct role in NF communication systems antenna design in particular, and stochastic electromagnetics in general.