RF currents induced in an anatomically-based model of a human for plane-wave exposures (20-100 MHz)

The three-dimensional finite-difference time-domain (FDTD) method has been used to calculate local, layer-averaged and whole-body averaged specific absorption rates (SARs) and internal radiofrequency (RF) currents in a 5628-cell, anatomically-based model of a human for plane-wave exposures from 20-100 MHz. The conditions of exposure of the human considered are: 1) isolated from ground, and 2) feet in contact with ground. Also considered are various separations of the model from ground and the use of insulating, rubber-soled footwear close to the grounded resonance frequency of 45 MHz. The calculated results are in agreement with the experimental data of Hill and others. While the existence of large foot currents has been known previously, substantial RF currents (600-800 mA) induced over much of the body are obtained for E-polarized fields suggested in the 1982 ANSI RF safety guideline.