Study on extremely anisotropic media and novel cloaking designs

Abstract

Metamaterials and invisibility cloak designs have drawn massive research interests in the past two decades. This thesis studies extremely anisotropic metamaterial and invisibility cloak designs for electromagnetic waves and diffusive fluid. We study the diffraction-free properties of extremely anisotropic media. We realize an extremely anisotropic metamaterial at microwave frequencies with a metallic-plate-stacking structure. With the metamaterial, we demonstrate the reflectionless diffraction-free electromagnetic wave routing at a broad bandwidth. Combining the extremely anisotropic metamaterial design and epsilon-near-zero media, we realize a metamaterial with permittivity approaching zero and infinity in two directions, and permeability approaching zero in the third direction, which is key to achieve omnidirectional impedance match. With the special metamaterial, we demonstrate an omnidirectional invisibility cloak at microwave frequencies. At last, we extend the cloak concept and propose a cloaking design for diffusive fluid. We use the geometry change of a single homogeneous isotropic material in the third dimension to realize the experimental demonstration of the diffusive fluid cloak.