Modelling line-of-sight coupled MIMO systems with generalised scattering matrices and spherical wave translations

A model to rigorously characterise line-of-sight MIMO systems is introduced. It is based on the generalised scattering matrix of each antenna, considered as isolated, and the rotation and translation coefficients of spherical modes. The resulting channel matrix rigorously includes the exact spherical vector nature of electromagnetic propagation (which may exert a significant influence over short-range links), mutual coupling effects and real antenna reflection, transmission, reception and scattering features. Numerical results are presented for MIMO systems made up of ideal dipoles.