Directional Invisibility of Elliptical Shaped All Dielectric Structure Induced by Evolutionary Optimization Approach

This study presents an optimal design of directional optical cloaking device based on evolutionary optimization approach. A cylindrical shaped perfectly electric conductor (PEC) material is selected as an object to be cloaked inside the proposed structure. Three-dimensional finite-difference time-domain method is combined with an optimization algorithm in order to numerically calculate and iteratively suppress the scattered fields due to the cylindrical shaped large ideal metallic scattering object. In particular, as optimization method Genetic Algorithm (GA) is employed. Here, optimization algorithm intelligently modulates the effective refractive index of the cloaking region by minimizing diffraction of the scattered field distribution in free space. The optimized cloaking structure composed of binary high refractive index (n(PLA) = 1.55) and low refractive index (n(air) = 1) elementary cells that are distributed in the optimization region. The structural and optical parameters of the proposed device are selected to be feasible in terms of fabrication by 3D printing technique and to make possible experimental verification at microwave frequencies in the future.