Propagation of Electromagnetic Waves Through an Invisible Gradient-Index Lens With Negative Refractive Index

A radially inhomogeneous (gradient-index) lens made of material with a negative refractive index, invisible from the viewpoint of geometrical optics, is proposed and designed. The design includes derivation and solution of an equation for determining the refractive index profile, as well as derivations of an expression allowing calculation of the ray trajectories in the lens. Propagation of a plane wave through a cylindrical modification of the proposed lens both for the case of E-polarization and for the case of H-polarization is analyzed numerically using the hybrid projection method. The results obtained for the radar cross section (RCS) of the lens are compared to the similar performance of a positive-index invisible cylindrical lens described in the previous publications.