A modified thin dielectric approximation for calculation of EM scattering by dielectric objects with thin material coating

The electromagnetic scattering by dielectric material sheet can be modeled in several different ways. In the integral equation approach to solve such a problem, there are surface equivalence method and volume equivalence method. When the thickness of a material sheet is much smaller than a wavelength, the thin dielectric sheet approximation (TDS) is often used. In this approximation, a volume equivalent problem is transferred to a surface integral equation for the material sheet, and hence number of unknowns is reduced. A major source of error in TDS is the lack of the vertical electric field component that is perpendicular to the sheet. This paper proposes a modification to TDS by adding the contribution of the vertical electrical field without increasing the computational cost. Numerical simulation results show that the accuracy is improved when this modification is employed.