Overlapped optics, illusion optics, and an external cloak based on shifting media

Based on optical transformation theory, an anistropic but homogeneous shifting medium is proposed to make multiple objects with the same shape appear as only one. Potential applications, e.g., enhancing the signal strength of current plane antennas and antenna arrays, are discussed in detail. Illusion optics, e.g., turning a spoon into a cup with an isotropic and homogeneous antiobject and a dielectric cup, is investigated. Such a homogeneous shifting medium can be extended to design an antiobject-independent external cloak. Finite element simulations for two-dimensional cases have been performed to demonstrate these properties.