Bandwidth of Invisible Cloak Realized with Split Ring Resonators

Recently, an uniaxial multilayer cylinder cloak which does not scatter electromagnetic wave was proposed. The purpose of this paper is to analyze such a cloak and to characterize the achieved "invisibility" in mathematical terms by calculating the scattered field and equivalent blockage width - the structure width that is actually "perceived" by EM waves. For that purpose we have developed the GIDMULT algorithm for analyzing uniaxial multilayer structures of planar, circular-cylindrical and spherical shape. The results show that the analyzed metamaterial realization reduces the scattered field and is suitable only for excitation by a TM-polarized wave. Furthermore, due to the dispersion it works only in a narrow frequency band. It seems that analyzed structure is inferior to already known realizations of invisibility, e.g. by hard surfaces that can work for arbitrary polarization within larger frequency bandwidth, although suitable for only one direction of incoming wave.