Equivalent medium theory of layered sphere particle with anisotropic shells

•Equivalent medium theory of layered spherical particle with anisotropic shells is found.•Various structure of anisotropic sphere is discussed.•The potential in the core-zone of particle is given.•The effect of core-shell geometric and electrical properties of particle shell on the inner electric field is analyzed.

Researches on the optical properties of small particle have been widely concerned in the atmospheric science, astronomy, astrophysics, biology and medical science. This paper provides an equivalent dielectric theory for the functional graded particle with anisotropic shells, in which inhomogeneous and anisotropic particle was equivalently transformed into a new kind of homogeneous, continuous and isotropic sphere with same size but different permittivity, and then greatly simplify the calculation process of particle׳s optical property. Meanwhile, the paper also discusses whether the charge on the particle can change the expression of its equivalent permittivity or not. These results proposed in this paper can be used to simulate the electrical, optical properties of layered sphere, it also meet the research requirement in the design of functional graded particles in different subjects.