A frequency-dependent FDTD method for induced-current calculations for a heterogeneous model of the human body

A weakness of the FDTD (finite-difference, time-domain) method is that dispersion of the dielectric properties of the scattering/absorption body is often ignored and frequency-independent properties are generally taken. While this is not a disadvantage for continuous-wave or narrowband irradiation, the results thus obtained may be higher erroneous for short pulses where ultrawide bandwidths are involved. A differential equation approach was developed. It can be used for general dispersive media for which in *( omega ) and mu *( omega ) may be expressible in terms of ration functions, or for human tissues where multiterm Debye relaxation equations must generally be used. The method is illustrated by means of one- and three-dimensional examples of media for which in *( omega ) is given by a multiterm Debye equation and for a dispersive model of the human body. >