Modified multi-layer TDS approximation for dielectric-coated targets

To solve scattering from a perfect electric conductor (PEC) with multi-thin-layer dielectric coatings, the multi-layer thin dielectric sheet (TDS) approximation is often used. In order to minimize inaccuracies in the determination of normal current distribution, the modified multi-layer TDS approximation is proposed in the paper. Normal unknowns, which differ from that in conventional multi-layer TDS, are redefined. Moreover, the explicit PEC boundary condition is employed with a minor modification. By using the modified approach, the thickness of the dielectric can be up to 0.3λ (λ is the dielectric wavelength). The improvement enables us to tackle a wider range of problems. A numerical example is given showing the validity of the proposed method.