Design of rotators based on coordinate transformation

Traditional cloak and rotator are obtained from mapping in single direction, either radial or tangential direction. However, this article proposed several novel structures obtained from mapping along multidirection, all of above designs are based on coordinate transformation theory. Those structures include "rotational cloak", "rota-tional concentrator", and so on, which are different from traditional structures. This paper discusses the optical properties of these novel structures; moreover, we have investigated the effects of various parameters on their properties, such as virtual radius and initial angle. Also,some interesting conclusions are drawn: 1) the energy convergent capability increases with virtual radius; 2) rotational angle of power flow direction depends on the value of initial angle and the location of optical source; 3) the permittivity and permeability of transformed material may be negative when virtual radius a greater than outer radius b, it is our well-known left-handed material.