Shielding Effectiveness of Metamaterial Cylindrical Arrays via the Method of Auxiliary Sources

Cylindrical arrays have been extensively used as key components of metamaterials (MMs) showcasing in a specific frequency range either an effective negative permittivity (ENG) or an effective negative permeability (MNG) or a double negative (DNG) behavior. ENG and MNG MMs may be used as electromagnetic (EM) shields via the mechanism of reflection, since their effective refractive index is purely imaginary, thus implying an evanescent wave in the MM and a total reflection of the incident wave. DNG MMs correspond to a negative refractive index and can function as absorbers of propagating waves provided that there is an impedance matching between the DNG MM and the surrounding medium; otherwise they function as a transparent material. The objective of this work is to study the shielding effectiveness (SE) of several ENG cylindrical arrays consisting of perfect electric conducting (PEC), dielectric
$\mathrm {B}a_{0.5} \mathrm {Sr}_{0.5} \mathrm {TiO}_{3}$
(BST), core-shell PEC-BST, and graphene-coated cylinders, by utilizing the method of auxiliary sources (MASs). Rectangular and circular arrays are considered and significantly high values of the SE are obtained. The MAS results are compared to those obtained by a commercial finite element method (FEM) software and an excellent agreement is observed in all examined cases.