NUMERICAL-SOLUTION OF INTEGRAL-EQUATIONS FOR DIELECTRIC OBJECTS OF PRISMATIC SHAPES

A numerical method is developed to investigate scattering from dielectric geometries of prismatic shapes. The surface integral equations are formulated by Schelkunoff's equivalence principle in terms of equivalent surface electric and magnetic currents. To solve these integral equations for the unknown currents, the object's cross section is mapped onto a circle. In the transformed space, Fourier type entire domain basis functions are used in the cross section and triangular subdomain basis functions are selected along the generating curve to represent the currents. A moment method is then used to reduce the integral equations to a matrix equation to compute the current coefficients. It is found that, the transformation of the objects surface to a circular shapes improves the convergence of the current modes in the cross-section. However, the current modes are coupled on the surface and the matrix equation includes all the modes. To examine the solution accuracy five different formulations are considered and used to investigate the scattering by a dielectric cube. The relative accuracy of the five formulations are compared. In this comparison the effect of surface modeling and basis function approximation is considered. Also considered is the effect that use of different formulations has on the spatial mode coupling.