Optimization of the method of auxiliary sources (MAS) for oblique incidence scattering by an infinite dielectric cylinder

The analytic inversion of the Method of Auxiliary Sources (MAS) matrix plays an important role in the rigorous investigation of the accuracy of the method. In this paper we investigate the accuracy of MAS when the method is applied to plane wave scattering under oblique incidence by an infinite, dielectric circular cylinder. For this scattering configuration, we prove that the MAS matrix is analytically invertible and hence obtain a concrete expression for the discretization error. A basic contribution of this paper lies in the analytic determination of the auxiliary sources' locations, for which the corresponding system's matrix becomes singular. Furthermore, we calculate the computational error resulting from numerical matrix inversion, and compare it to the analytical error. The dependence of both types of errors on the angle of incidence and on the dielectric permittivity is investigated. Finally, error minimization indicates the auxiliary sources' optimal location.