Extreme electromagnetic boundary conditions

The singularities in the fields and polarization densities at the inner surfaces of spherical and circular cylindrical cloaks illuminated by sources inside their cavities are shown to obey generalized electromagnetic boundary conditions that are derived for interfaces containing surface layers of electric and magnetic polarization. For sources inside the cloak cavities, it is found that the inner surfaces of spherical cloaks, unlike the inner surfaces of cylindrical cloaks, behave as “DB boundaries” at which n · D and n · B are zero.