Characterization of Reactive Energy Density in the Antenna Near-Field using EM Lagrangian Density

In this paper, we propose the use of period-averaged EM Lagrangian density for the efficient frequency-domain characterization of reactive energy density around arbitrary antennas. First, we correlate this period-averaged EM Lagrangian density, a quantity less explored in the antennas and propagation community, with the popular complex Poynting’s theorem. Next, by using full-wave computational EM solver, we plot the 2D spatial maps of EM Lagrangian density in the near-field of a thin-wire V-dipole antenna for different flare angles. Such spatial maps can provide vital insights into the radiation mechanism and near-field structure of generic antennas, by unveiling the capacitive and inductive nature of the non-propagating reactive energy density.