An FDTD-IDM-CGF Method for Investigating Correlation, Mutual Coupling and Energy Dynamics in Antenna Systems

In this paper, we present a unified computational scheme FDTD-IDM-CGF, which combines the well-known finite-difference time-domain (FDTD) technique with the infinitesimal dipole modelling (IDM) and cross-correlation Greens functions (CGF). The proposed FDTD-IDM-CGF methodology is extremely useful for investigation of fundamental problems pertaining to spatial correlation, mutual coupling and spatio-temporal near-field energy in general antenna systems. Considering a system of two closely spaced thin-wire dipoles, we analyze both far-field correlation coefficients and newly introduced near-field electric/magnetic correlation coefficients using the FDTD-IDM-CGF approach. Besides some crucial insights into the connection between mutual coupling and near-field correlation coefficients, some additional observations regarding the temporal Poynting energy dynamics are also provided.