Broadband, polarization-insensitive and temperature-independent metamaterial absorber based on graphene hybrid water in terahertz domain

Water and graphene have been used separately to effectively broaden absorption bandwidth in the design of metamaterial absorbers (MAs). In this paper, a broad terahertz MA is presented, in which water and graphene are used together for improving absorption performance. The absorptivity of the presented MA exceeds 90% over the frequency range of 2.81–6.74 THz. It is found that the proposed MA has superior absorption performance to those using water or graphene separately. The impedance matching theory as well as the distribution of the field and power loss are used to provide a deep insight into the absorption mechanism. Furthermore, the proposed MA exhibits excellent thermal stability as well as good insensitivity to polarization and incident angle. This work provides a reference for designing broadband MA in terahertz frequency band.