Analysis On Effective Permittivity Of Coated Ellipsoid And Design Of Metamaterial

The permittivity and permeability are the most important electromagnetic parameters in the research and design of metamaterials.There are two main ways to obtain the permittivity and permeability,i.e.,parameter retrieval and analytical method.Analytical methods contain classical effective medium theory and internal homogenization.The internal homogenization is adopted to get the effective permittivity of the coated cylinder,coated sphere and coated ellipsoid in this work.After that,the change tendencies of effective permittivity are studied when the dimensions and the constitutive materials of the above coated structures are changing.And the approximate formulas of different models for different materials are derived,which can be applied in designing various devices with desired electromagnetic properties.Based on the solved effective permittivity,a focus lens composed of the coated ellipsoid is simulated in the electromagnetic simulation software HFSS and the simulation result verifies the accuracy of the deduced expression.The theoretical deduction and numerical simulation have indicated that the accurate results of coated cylinder,coated sphere and coated ellipsoid can be obtained with electromagnetic analytical expressions based on the theory of internal homogenization.The focusing effect has been achieved for the focus lens using the deduced effective permittivity.Moreover,the approximate expressions obtained are of great help to design electromagnetic devices.They have a very clear physical picture,a simple form and can improve the calculation efficiency,which have specific value of utilization.