%?????The?dimensions?of?the?computational?domain?are?8.2?cm??
%?????（x-direction）?3.4?cm?（y-direction）?and?3.2?cm?（z-direction）.????
%?????The?grid?is?terminated?with?UPML?absorbing?boundary?conditions.??
%??
%?????An?electric?current?source?comprised?of?two?collinear?Jz?components??
%?????（realizing?a?Hertzian?dipole）?excites?a?radially?propagating?wave.????
%?????The?current?source?is?located?in?the?center?of?the?grid.??The???
%?????source?waveform?is?a?differentiated?Gaussian?pulse?given?by???
%??????????J（t）=J0*（t-t0）*exp（-（t-t0）^2/tau^2）???
%?????where?tau=50?ps.??The?FWHM?spectral?bandwidth?of?this?zero-dc-??
%?????content?pulse?is?approximately?7?GHz.?The?grid?resolution???
%?????（dx?=?2?mm）?was?chosen?to?provide?at?least?10?samples?per???
%?????wavelength?up?throug