Currents induced in the human body for exposure to ultrawideband electromagnetic pulses

The frequency-dependent finite-difference time-domain [(FD)/sup 2/TD] method is used to calculate internal electric fields and induced current densities in a 1.31-cm resolution anatomically-based model of the human body for exposure to ultrawideband vertically polarized electromagnetic pulses (EMPs). From a single (FD)/sup 2/TD simulation, two ultrawideband pulses with frequencies up to 1500 MHz are examined using a convolution technique. The complex permittivities /spl epsiv/*(/spl tau/) for the various tissues are known to vary a great deal over the wide bandwidth of these two pulses. In the (FD)/sup 2/TD formulation, these frequency-dependent /spl epsiv/*(/spl tau/) are described by the best-fit second-order Debye equations for the sixteen tissues that are used to define the anatomically based model. The vertical currents passing through several sections of the body are compared for a shoe-wearing model standing on a perfectly conducting ground plane, and a barefoot model suspended in air. For the first pulse, currents on the order of 1 to 4 mA per V/m of incident fields are calculated with the highest values calculated for the sections through the bladder and slightly above it. For the second pulse, currents on the order of 4 mA per V/m of incident fields were calculated.