Equivalent layers of surface charge, current sheet, and polarization in the eigenfunction expansions of Green's functions in electromagnetic theory

The discontinuous behavior of the eigenfunction expansion of various Green's functions commonly used in electromagnetic theory is discussed with the aid of equivalent layers of surface charge, current sheet, and surface polarization. Green's function pertaining to the potential function in electrostatics is discussed first, followed by a detailed analysis of an eigenfunction representation of a typical dyadic Green's function for time-varying harmonic fields.