Broadband terahertz metamaterial absorber based on tantalum nitride.

A broadband metamaterial absorber with a single layer of tantalum nitride (Ta₂N₃) frequency selective surface layer, printed on a foam substrate, is presented. The proposed design has been numerically examined at the terahertz region. The results have shown that a wideband absorption with absorptivity greater than 90% was achieved in the frequency range 1.17-2.99 THz, and the relative absorption bandwidth was up to 112.97%, which is significantly better than previously reported results. Moreover, the absorber was independent of wave polarization, and a high absorption for a wide range of oblique incidence was achieved. The surface current distribution, the electric field distributions, and the power loss analyses were used to explain the physical mechanism of a wideband absorption. However, the tantalum nitride layer has an important role in the energy absorption. According to the obtained results, the proposed absorber, which is compact and simple to design, has a potential application in evolving broadband terahertz absorbers and sensors.