Finite Element Analysis of Electromagnetic Scattering from Inhomogeneous Cylinders at Oblique Incidence

A finite element formulation of electromagnetic scattering from composite material cylinders at oblique incidence is presented. The cylinders are uniform along their axis which, without loss of generality, is assumed to be parallel to the z axis of a Cartesian coordinate system, while their cross section is of arbitrary shape and composition. The excitation can be either a plane wave of arbitrary polarization at oblique incidence with respect to the cylinder axis, or any traveling-wave field with z dependence of the form exp (- iβz). The weighted-residual statement of the problem involves the z components of the electric and magnetic field, and is such that the continuity of the tangential electric and magnetic fields at media interfaces is directly enforced. The finite element solution is carried out using the bymoment method. Numerical results for echo widths and field distributions within cylinders of various shapes and compositions are presented. Comparisons of some of the results with those obtained from exact eigenfunction expansion and integral equation solutions demonstrate the validity of the method and the associated computer program.