New considerations on electromagnetic energy in antenna near-field by time-domain approach

In this paper, the problem of determining electromagnetic energy in the near-field of antennas is critically revisited. It is emphasized why one must look beyond the traditional antenna-Q factor and investigate near-field EM energy from a time-domain approach. A finite-difference time-domain (FDTD) simulation strategy for calculating reactive energy near radiating structures is described briefly. Finally, some new aspects pertaining to time-evolution and visualization of the near-field energy distributions are described, that can be tackled with this FDTD-based methodology.