Metasurface-Epsilon Near Zero-based electromagnetic wave absorber

The purpose of this paper is to design a new electromagnetic wave absorber. It consists of a planar layered structure with an isotropic Epsilon-Near-Zero (ENZ) material and a gold metal inclusion, both placed over a perfect conductor (PEC) plate. Absorption is obtained by exploiting the combination of both ENZ and metasurface materials. The electromagnetic properties of the structure, in terms of reflection coefficient, are analytically described by the use of the transmission line theory. The proposed analytical closed-form formula provides us the possibility to correlate the electromagnetic absorption properties of the structure (magnitude, bandwidth and resonant frequency) with its geometrical characteristics. Such a formula represents a useful tool in order to design the absorber for specific required applications. The main issue is to absorb the incident electromagnetic wave in the broadest angle range possible. In particular, an absorption in a wide angle range (0°-80°), for different frequencies (multi-resonant), with a large frequency bandwidth (wide-band) for small structure thicknesses (d<λr/4) is demonstrated, compared to the conventional absorbers existing in literature.