Characteristic-based finite-volume time-domain method for scattering by coated objects

The characteristic-based finite-volume time-domain method is applied to ana lyze the scattering from conducting objects coated with lossy dielectric ma terials. Based on the characteristic-based finite-volume scheme, two numeri cal strategies are developed to model the electromagnetic propagation acros s different dielectric media. One introduces a connecting boundary to separ ate the total-field region from the scattered-field region. The other emplo ys the scattered field formulation throughout the computational domain. The se two strategies are verified by numerical experiments to be basically equ ivalent A numerical procedure compatible with the finite-volume scheme is d eveloped to guarantee the continuity of the tangential electric and magneti c fields at the dielectric interface. Rigorous boundary conditions for all the field components are formulated on the surface of the perfect electric conducting (PEC) objects. The numerical accuracy of the proposed technique has been validated by comparison with theoretical results.