Thin Dielectric Sheets Approximations for EM Scattering from Layered Dielectric Structures

In this paper, a multi-layer TDS (Thin dielectric sheets) model is proposed to simplify the Volume integral equation (VIE) based on the TDS approximations when we solve the Electromagnetic (EM) scattering from layered dielectric structures. The tangential components of polarization current in each layer are approximated to linear variation along the transverse direction while constant in the normal direction. Similarly, the normal components are approximated to vary linearly in the normal direction and keep constant within a small patch in the tangential direction. Based on these approximations, and the divergence free and normal continuity conditions of D flux, a set of recursive formulations are derived out to reduce the number of independent basis functions, which are used to construct the polarization current. Then, we can further approximate the volume integrals in VIE to some surface integrals for far filed evaluation. The above TDS approximations can alleviate the difficulty of geometry discretization, reduce the number of unknowns, and shorten the time consumption of numerical calculation. The computational complexity of numerical simulation is reduced significantly.