In this paper, a liquid crystal (LC) based tunable metamaterial absorber with dual-band absorption is presented. The proposed absorber is analysed both numerically and experimentally. The analysis shows that the two absorption peaks, originating from the new resonant structure, are experimentally detected at 269.8 GHz and 301.4 GHz when no bias voltage is applied to the LC layer. In order to understand the absorption mechanisms, simulation results for the surface current and power loss distributions are presented. Since liquid crystals are used as the dielectric layer to realize the electrically tunable absorber, a frequency tunability of 2.45% and 3.65% for the two absorption peaks is experimentally demonstrated by changing the bias voltage of the LC layer from 0 V to 12 V. Furthermore, the absorber is polarization independent and a high absorption for a wide range of oblique incidence is achieved. The designed absorber provides a way forward for the realization of tunable metamaterial devices that can be applied in multi-band detection and imaging.
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.
This article proposes and experimentally demonstrates an optically transparent and polarization‐insensitive metamaterial absorber in the terahertz (THz) frequencies. The absorber is formed by indium‐tin‐oxide (ITO) resistive films, providing efficient absorption with absorptivity of 94.1% at the peak absorption frequency of 120.8 GHz. We systematically investigate the surface current distribution and the power loss analysis, and explain the architecture of the absorber. Moreover, the absorber exhibits unique absorption properties at resonant frequencies, that is, featuring single‐band or dual‐band operation by changing the surface resistance of the ITO patterns. In addition, the experimental demonstration and measurement results are in good agreement with the simulated results. Most importantly, the fabricated absorber exhibits an optical transparency above 70% over the entire visible waveband, thereby enabling a wide range of applications such as optically transparent THz absorbers and detectors.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.