Approximated Complementary Cloak With Diagonally Homogeneous Material Parameters Using Shifted Parabolic Coordinate System

In this communication, a parabolic shaped complementary cloak is proposed which makes the object invisible by reducing its scattering under different incidence angles of electromagnetic wave. The proposed design is based on transforming a line segment into an enclosed space that is surrounded by the core region. The enclosed space is symmetrically divided into two regions, namely, cloaked region and complementary region. The shifted parabolic coordinate system introduced in the present work enhances the area of cloaked region and provides diagonally anisotropic but optimized homogeneous material properties in the core region. The cloaked region is mapped onto the complementary region using a simple one directional folding transformation, which yields homogeneous and isotropic material properties in the complementary region and also eases the creation of antiobject. Numerical results confirm the cloaking effect of the proposed approximate complementary cloak. The metamaterial unit cell designs are also presented for realizing the proposed material properties of core and complementary regions.