Analysis and design of wire-based metamaterial absorbers using equivalent circuit approach

Abstract

Wire-based metamaterial absorbers, as a kind of simple but versatile artificial structures, have been widely investigated from microwave to optical frequencies. In order to completely understand how the constitutive parameters affect the absorption properties, an equivalent circuit model is developed in this paper. The analytical, numerical, and experimental results show that the absorption frequency is determined by the wire length and the spacer electromagnetic parameters, whereas the absorption level by the thickness of spacers and losses which include Ohmic loss of the metal as well as dielectric loss of the spacers. It is also explained why the small losses have hardly any effect on the absorption frequency, but can result in the near-unity absorption. Based on the circuit model, some strategies for designing broadband absorbers are discussed finally.

A Novel Six-Band Polarization-Insensitive Metamaterial Absorber With Four Multiple-Mode Resonators

“…Thus, the inductance L can be extracted according to the surface current distribution for each absorption frequency. The inductance L can be approximated by the formula: L = μ * h * l/w [28,29]. μ is the permeability of the dielectric, and l and w are the length and width of the metal which the surface current flows through.…”

Ultra-Compact Metamaterial Absorber With Low-Permittivity Dielectric Substrate

“…Therefore, the resonance frequency decreases rapidly. At the same time, the equivalent impedance [27] of the MA also changes to inductive domain, and the MA becomes impedance mismatch to the background space. It should be noted that before we get the final MA size, we do not focus on the impedance match because it is easy to be realized by changing the substrate thickness which will be performed later.…”

“…Moreover, strategies for expanding the operating bandwidths of MAs, such as dual-band [14,15], triple-band [16,17], multiband [18,19], band-tunable [20,21], broad-band [22,23], and ultra-broad-band [24,25] designs, have also been reported in recent years. Simultaneously, the theoretical analysis methods including classic electromagnetic theory [7], interference theory [26], and equivalent circuit/transmission line theory [27] are developed to analyze and guide the design procedures and explain the appeared exciting absorbing properties.…”

Equivalent circuit model of an ultra-thin polarization-independent triple band metamaterial absorber

“…[13][14][15][16][17][18] Till date, various designs for choice of geometrical parameters for a perfect metamaterial absorber have been investigated. 18,19 However, most of them are limited to the discussion on single band absorber. 20,21 In this paper, three concentric circular-shaped CRR structures embedded in a single unit cell have been designed which can be used for triple band absorber.…”