Design of Double Negative Metamaterial Thin Absorber

This paper presents a new type of thin absorber exhibiting double negative metamaterial (MTM) characteristics. A MTM unit cell was constructed by a multiple split ring resonator (MSRR) and a meander-line arrangement. A MSRR structure exhibits negative permeability and a meander-line structure exhibits negative permittivity. Each unit cell is printed on the two side of a FR-4 substrate (relative dielectric constant = 4.4, thickness = 0.8 mm). The proposed one-layer absorber based on double negative MTM was shown to reach thickness of the order of lambda(0)/250 at the aimed frequency of 1.55 GHz. In order to maximize the absorption per unit volume, ten unit cells disposed in an array configuration were considered. Simulated results show a high maximum absorption of 95% at 1.52 GHz. In the design of the double negative MTM unit cell, the complex permittivity and permeability of the cell were retrieved from scattering parameters.