Invisibility cloak without singularity
  An elliptical invisible cloak is proposed using a coordinate transformation in the elliptical-cylindrical coordinate system, which crushes the cloaked object to a line segment instead of a point. The elliptical cloak is reduced to a nearly-circular cloak if the elliptical focus becomes very small. The advantage of the proposed invisibility cloak is that none of the parameters is singular and the changing range of all parameters is relatively small. 
Wei Xiang Jiang, Tie Jun Cui, Xin Mi Yang, Qiang Cheng, Ruopeng Liu,   and David R. Smith