FORMULATIONS OF THE EXTENDED BOUNDARY-CONDITION METHOD FOR INCIDENT GAUSSIAN BEAMS USING MULTIPLE-MULTIPOLE EXPANSIONS

Novel formulations for improving the numerical stability of the extend ed boundary conditions method and extending its application to highly elongated dielectric objects illuminated by a Gaussian beam are descri bed. The derived formulations are obtained as special cases of a gener al approach, which considers arbitrary complete system functions on th e particle surface. The surface currents are approximated by multiple spherical expansions or, for a fixed azimuthal mode, by the lowest-ord er multipoles located inside the particle surface. Results illustratin g the application of the procedures developed are presented.