Broadband tunable coding metasurfaces based on a metal patch and graphene for beam control at the terahertz frequencies

Abstract

We present a broadband tunable coding metasurfaces structure using a cruciate metal patch and circular graphene on a multilayer substrate. By changing the Fermi level of the graphene, we can achieve obvious reflection phase variation to design multi-bit coding metasurfaces. In the research of 1-bit coding metasurfaces, we combine the advantages of graphene and copper to realize the real-time adjustment of the reflected waves in four broadband frequency bands. In this case, we can control the number of far-field reflected waves in the frequency range of 5.45–6.45 THz. Then, we create 2-bit and 3-bit coding modes on the basis of 1-bit coding metasurfaces to obtain a single beam of reflected waves. Finally, we use the convolution calculation to realize the real-time adjustment of the single beam reflection direction from 0° to 360° in the azimuthal plane. Research of the 2-bit and 3-bit coding modes also provides a way to control the number and direction of the reflected beam, specifically in the 1-bit coding mode. The present coding metasurfaces structure provides inspiration for the design of functional devices in future-oriented intelligent communication.

Analysis and design of terahertz reflectarrays based on graphene cell clusters

“…They possess some dynamic control ability and adjustability. These unit cells may be made up of adjustable liquid crystals 14 , graphene paches 15 , graphene and metal patches 16 , metasurfaces with electromagnetically induced transparency (EIT) technology 17 , and metasurfaces with plasma induced transparency (PIT) technology 18 .…”