Internal field analysis for scattering of electrically small multilayer spherical scatterers

Abstract

The Mie theory provides a general electrodynamic method for calculating the scattering coefficients of the internal electric and magnetic fields induced in a multilayer spherical scatterer. Moreover, the use of Taylor and Padé expansion methods paves the way for physically interpretable mathematical forms of the Mie scattering coefficients. This study utilizes the Taylor approximation method along with the idea of equivalent core and ambient permittivities to reformulate the Mie coefficients for induced internal electromagnetic fields of electrically small multilayer spherical scatterers. The procedure begins with a typical triple-layer scatterer, and the formalism is further generalized to express induced fields for an M-layer scatterer. The equivalent core and ambient permittivities let acquisition of new perspective on the subject of internal fields induction, and make it easier to synthesize inclusions with unconventional electromagnetic properties. The deep distinction between equivalent core and ambient permittivities is revealed through further illustration of their variations for a typical quadruple-layered structure.