Wide incidence angle and polarization insensitive dual broad-band metamaterial absorber based on concentric split and continuous rings resonator structure

Abstract

A new design of a metamaterial absorber (MMA) with two broad-bands is simulated, fabricated and experimentally investigated in this paper. The MMA structure unit cell consists of combination of eight rings with two pair of concentric split rings and two pair of concentric continuous rings placed diagonally opposite. The proposed MMA has x-y symmetrical copper unit cells with middle layer of FR-4 substrate and copper laminated ground plane. The simulated and measured absorption peaks as well as the absorptance of the proposed MMA exhibits insensitivity to change in polarization and incidence angle of electromagnetic waves. The metamaterial behavior of the studied MMA is confirmed by extracting effective permeability, μeff(f), effective permittivity, εeff(f), and effective refractive index, ηeff(f), from the measured S-parameters. The proposed MMA has resonance peaks at 7.6 GHz, 8.9 GHz, 12.3 GHz, and 12.8 GHz with measured absorptance of 94%, 99.9%, 96%, and 96% at respective frequency bands. The first absorption broad-band extends from 7.36 GHz to 9.36 GHz and the second broad-band extends from 11.9 GHz to 13 GHz. The high electromagnetic wave absorptance from 7.36 GHz–9.36 GHz and 11.9 GHz–13 GHz makes this MMA suitable for satellite, mobile and radar applications.