A modeling approach for simulating MIMO systems with near-field effects

A hybrid method of modeling MIMO systems is presented through the combined use of full-wave electromagnetic (EM) simulations and statistical channel models. This approach consists of simulating each antenna in the antenna array to compute its embedded element pattern including all of the near-field electromagnetic and coupling effects. These embedded patterns are then uploaded into the measurement-based statistical spatial channel model (SCM) to study the link-level performance of the MIMO system. The equivalence between the coupling matrix of an antenna array and the embedded element pattern of each antenna is theoretically derived and verified. We compute the channel matrix in two approaches. First, either the theoretically calculated or the simulated embedded radiation patterns are used with SCM to compute the channel matrix. Second, the coupling matrix is used with the default SCM algorithm to compute the channel matrix. Then, the MIMO system capacity is computed and compared. The results show very good agreement between the two approaches. Our approach is general as it includes the detailed near-field EM effects such as the effects of the case and the user on the handset MIMO system.