Design of transparent cloaks with arbitrarily inner and outer boundaries

In this paper, the efficient transformation optics method has been utilized to design and analyze two-dimensional (2D) transparent cloaks, structures that can physically protect the devices inside but do not affect their electrical performances at all. The general and explicit expressions for the material parameters of the transformed space are derived. 2D transparent cloaks with arbitrarily conformal and nonconformal inner and outer boundaries and those working in gradually changing background and layered media are designed. Full-wave simulations combined with the Huygens’ principle are applied to validate the transparency of the cloaks. The simulation results under different circumstances demonstrate that the proposed method is correct and efficient. The work introduced here makes important progress in the theoretical design of the transparent cloak and expands the application of the transformation optics method.