Diffraction in the high frequency regime by a thin layer of dielectric material I: The equivalent impedance boundary condition

We discuss in this paper a generalized impedance boundary condition that can be used locally to replace a thin layer of material with dielectric absorbing constants. This condition takes into account the curvature of the body and the angle of incidence of the incident wave, which can be more general than a plane wave. We use this condition to obtain a system of equations outside the object equivalent to the system of Maxwell equations.