  We propose a finite difference method to solve Maxwell's equations in time
domain in the presence of a perfect electric conductor that impedes the
propagations of electromagnetic waves. Our method is a modification of the
existing approach by Zou and Liu [36], from a locally perturbed body-fitted
grid to a uniform orthogonal one for complicated PEC objects. Similar to their
work we extrapolate ghost point values by exploiting the level set function of
the interface and the PDE-based extension technique, which allows us to
circumvent scrutinizing local geometries of the interface. We stipulate a mild
requirement on the accuracy of our extrapolation that the ghost values need
only be locally second order accurate. Nevertheless the resulting accuracy of
our method is second order thanks to the application of back and forth error
correction and compensation, which also relaxes CFL conditions. We demonstrate
the effectiveness of our approach with some numerical examples.
