OBLIQUE SCATTERING FROM RADIALLY INHOMOGENEOUS INFINITE CYLINDERS OF LARGE RADIUS

A new method for scattering from radially inhomogeneous cylinders of l arge radius is presented herein. It is based on the Coupled Azimuthal Potentials (CAP) Formulation [1], i.e., a description of the fields in terms of magnetic and electric azimuthal potentials. Since the cylind ers considered are in 2D geometry of revolution, they are split in con centric layers where the Gaussian profile of the permittivity is appro ached by a piecewise constant function. The novelty of the method is t o solve directly Maxwell's equations for a permittivity varying contin uously radially, in terms of modal tangential electromagnetic fields, by making the steplength of the layers tend to zero. This allows us to minimize the size of linear systems. Properties of the potentials are used only on the cylinder axis and at infinity. The potential coeffic ients are developed by using cylindrical functions to express the boun dary conditions. Then, asymptotic approximations are used to determine the diffracted fields at infinity. Numerical results of near-field ma p are compared with others obtained via the Finite Element Method code s. But these codes require quite small meshes and are thus limited in size of geometry. Moreover, polarized and depolarized scattering width s are presented which show the depolarization of the diffracted field for both TE and TM polarizations of the incident field. It is revealed that the fields are noticeably modified by the medium and that the an gle of incidence has a great influence on the levels of scattering wid th.