Imperfect Cloaking Devices Based on Metamaterials

Cloaking devices designed using the coordinate transform approach were shown to be realizable, at least in principle, within the realm of electromagnetic metamaterials. In this paper we investigate the strictness of conditions imposed on the parameters of metamaterial cloaks by calculating the degree of wave scattering when those parameters have variations with respect to theoretically ideal values. A simple idea is used to obtain analytic results for the case of the nonideal two-dimensional cloaking cylinder. Also, results of realistic finite element simulations of the Helmholtz equation are presented and it is found that they are in excellent agreement with the analytic results.