Electromagnetic Scattering from Dielectric Objects Using the Eigenmode Projection Technique

Electromagnetic scattering by dielectric objects is analyzed using an eigenmode projection technique. A fictitious canonical cavity is chosen to enclose the illuminated scatterer, and the fields are expanded in terms of the cavity solenoidal and irrotational eigenmodes. The surface of fictitious cavity is regarded as a port excited by the incident wave, and the cavity fields and the port fields are then matched on the surface resulting in the cavity mode and port field coefficients. The frequency independent feature of the generated matrices is exploited to provide an efficient solution over a wide range of frequencies without the need of filling and inverting all the system of matrices and the numerical integrations are only evaluated once, with their values used at all frequencies. The technique also lends itself to problems, where variations of the same structure are to be analyzed, with the perturbations not necessarily small as long as they are bound by the same canonical cavity. Results are presented to validate the method and illustrate the speed up of the technique in wideband and perturbation analysis.