Metamaterial with dual stealth functions in infrared and terahertz bands

In this study, an electromagnetic metamaterial with infrared (IR) passive stealth and terahertz (THz) active stealth functions is proposed. The device comprises an infrared stealth layer (IRSL) made of ZnS and SiO2, and a terahertz absorbing layer (TAL) utilizing a "graphene-SiO2-gold" sandwich-like structure. The properties of the metamaterials are investigated using the full-vector finite element method. The results indicate that the emissivity of the device is close to zero in the infrared atmospheric window (8 ~ 14 μm), with an absorption of up to 88% and a bandwidth of 2.54 THz at the center frequency of 3.98 THz. Furthermore, the device exhibited polarization insensitivity and tolerance to wide-angle incidence. These advantages make it suitable for applications in the THz radar and stealth fields.