Ultra-low reflection of sub-THz waves in graphene-based composite with metasurface for stealth technology

Sub-wavelength metasurfaces offer opportunities to develop efficient stealth technologies that are increasingly significant in modern civil and military applications. Here, we demonstrate that a highly efficient flexible graphene-based composite sub-THz radiation absorber can also act as an ultra-low reflection material with reflectivity as low as 0.12%. To enable this, we employ a surface modification of the composite with periodic shapes designed to harness the sub-wave low reflection mechanism for a given frequency - at 96.9 GHz that is within the range of the atmospheric radio window. The terahertz goniometric system measurements show that the fabricated metasurface works for terahertz waves with two polarization directions (S and P) and exhibits material characteristics with polarization independence. Our work offers an alternative approach for designing and fabricating a flexible metasurface for efficient antireflection and stealth application.