Experimental investigation of omnidirectional multiphysics bilayer invisibility cloak with anisotropic geometry

Abstract

Abstract Thermal-electric bilayer invisibility cloak can prevent the heat flux and electric current from touching the object without distorting the external temperature and electric potential fields, simultaneously. In this paper, we design an omnidirectional thermal-electric invisibility cloak with anisotropic geometry. Based on the theory of neutral inclusion, the anisotropic effective thermal and electric conductivities of confocal elliptical bilayer core-shell structure are derived, thus obtaining the anisotropic matrix material to eliminate the external disturbances omnidirectionally. The inner shell of the cloak is selected as insulating material to shield the heat flux and electric current. Then, the omnidirectional thermal-electric cloaking effect is verified numerically and experimentally based on the theoretical anisotropic matrix and manufactured composite structure, respectively. Furthermore, we achieve the thermal-electric cloaking effect under a specific direction of heat flux and electric current using the isotropic natural materials to broaden the selection range of materials. The method proposed to eliminate anisotropy and achieve the omnidirectional effect could also be expanded to other different physical fields for the metadevices with different functions.