Schematic, composition, and equivalence of the ghost-illusion device. (a) The original metallic object with its scattering signature given in panel (d). (b) The metallic object covered by the designed ghost device and the corresponding scattering signature in panel (e). (c) A shrunk metallic object at the original center with two wing dielectric objects, whose signature is given in panel (f). The scattering signatures of (b, c) are completely the same. In the far-field calculation, the geometrical parameters are chosen as a = 3.8λ₀, a′ = 1.63λ₀, b′ = 5.4λ₀ and c = 7λ₀. Reprinted (figure) with permission from reference [39]. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.