An extended equivalent source technique for calculating scattering and absorption by electrically long and composite dielectric objects

A novel method for improving the numerical stability of the iterative extended boundary condition method (IEBCM) and extending its application to highly elongated and composite dielectric objects is described. This procedure has three main features: it utilizes multiple spherical expansions to describe the fields both inside and outside the dielectric object; it uses a direct point-matching procedure to determine the unknown expansion coefficients; and point-matching is combined with least-square fitting to determine the unknown expansion of coefficients. Results illustrating the application of the developed procedure to electrically large dielectric objects at and beyond their resonant frequencies are presented.<>