Physical Insights Into Cylindrical Illusion Device With Isotropic and Homogeneous Materials

The cylindrical illusion device with isotropic and homogeneous materials is studied deeply based on the Mie scattering theory. The formula for illusion of core-shell structure is derived in the quasistatic approximation. Whether the inner core is a dielectric or PEC material, it can be equivalent to a certain target cylinder after wrapping a properly designed shell. We investigate what range of permittivity of the shell may be possible to achieve a target, which can provide convenient and intuitive design charts for an approximate design a core-shell illusion device. It is found that the number for the thickness of the shell is zero, one or two when the permittivities of the target and the shell take a variety of parameters. Moreover, the physical insights into the parameters' distribution are explained by analyzing the electric dipole moments in each part of the core-shell structure. It is interesting to see that a double negative material can be equivalently achieved by a PEC core coated with a positive magnetic material, which may offer a new design approach for the realization of double negative materials. The scattering widths and full-wave simulations are given to verify correctness of the proposed method.