  Ultra-wideband (UWB) electromagnetic pulses of nanosecond duration, or
nanopulses, are of considerable interest to the communications industry and are
being explored for various applications in biotechnology and medicine. The
propagation of a nanopulse through biological matter has been computed in the
time domain using the finite difference-time domain method (FDTD). The approach
required existing Cole-Cole model-based descriptions of dielectric properties
of biological matter to be re-parametrized using the Debye model, but without
loss of accuracy. The approach has been applied to several tissue types.
Results show that the electromagnetic field inside a biological tissue depends
on incident pulse rise time and width. Rise time dominates pulse behavior
inside a tissue as conductivity increases. It has also been found that the
amount of energy deposited by 20 $kV/m$ nanopulses is insufficient to change
the temperature of the exposed material for the pulse repetition rates of 1
$MHz$ or less.
