A tunable broadband terahertz MoS₂ absorber using series-parallel hybrid network design

A method for designing a broadband absorber using a series-parallel hybrid network is proposed. The performance of the broadband absorber is improved by using frequency-selective surface patterns based on a series-parallel hybrid equivalent circuit. The results indicate that the tunable single-layered terahertz MoS₂ absorber has excellent broadband characteristics. Between 0.84 and 2.34 THz, the absorption and relative absorption bandwidth exceed 90% and 94.3%, respectively. Also, the absorption level can be adjusted from 90% to 10% by applying a bias voltage on the electrodes. The effects of different types of MoS₂ layers and surface fluctuations in monolayered MoS₂ on the properties of the absorber are demonstrated. In the 60° (TM) and 50° (TE) ranges, the polarization of the terahertz absorber is insensitive to the incidence angle. Overall, this method enables the single-layered absorber to exhibit excellent broadband characteristics comparable to those of multilayered structures, as well as simplifies the structure. Consequently, this method significantly broadens the usefulness of tunable single-layered absorbers for radar stealth, terahertz imaging, and electrically tunable modulation.