Numerical techniques for evaluating electromagnetic field propagators

We review a series of electromagnetic field propagator expressions and their numerical solutions. These include propagators arising from a spectral-frequency domain scalar Helmholtz equation solution evaluated by a Fast Fourier transform numerical method, a full wave vector spectral-spatial domain expression solved by an implicit Fourier transform method, and a full wave time domain tensor field expression solved by an explicit integration technique. It is shown that the tensor field explicit integration method has some computational and accuracy advantages over differential equation finite difference methods.