Optimization of Uniaxial Multilayer Cylinders Used for Invisible Cloak Realization

Uniaxial cylindrical cloaks have recently been proposed to prevent scattering of electromagnetic waves, i.e., to render objects invisible. While it is possible to achieve that the rays follow the proper path inside the cloak, the proposed cloaks with reduced variation of constitutive parameters suffer from nonzero reflectance. The purpose of this paper is to improve invisibility performance of the original cloak structure in terms of total scattering width reduction and the operating frequency bandwidth. Therefore, the program for analyzing uniaxial cylindrical structures is merged with the global optimization program based on the particle swarm optimization algorithm. The results show that it is possible either to obtain the “perfect” cloak at the expense of bandwidth or to improve the operating frequency bandwidth at the expense of limited reduction of total scattering width.