Reconfigurable Metasurface for Nearly Full-Range and Continuous Modulation of Reflection, Transmission, and Absorption

Reconfigurable metasurfaces with versatile functionalities are highly demanded for various practical applications. In this paper, a varactor-based metasurface is proposed for dynamic and continuous modulation of reflection, transmission, and absorption in a single design. The proposed metasurface consists of a dielectric layer sandwiched by two metallic layers with different patterns, and varactors are loaded on both metallic layers. By controlling the bias voltages applied to the varactors, this metasurface can exhibit nearly full-range and continuous modulation of reflection, transmission, and absorption. Particularly, nearly perfect reflection, transmission, and absorption have been achieved by proper combinations of bias voltages. Coupled mode theory is further developed to offer a physical insight of the metasurface. The above concept is confirmed by numerical simulations and experiments in a microwave waveguide system. As this proposal concerns a metasurface with high degrees of freedom, it may find practical applications including radar cross-section reduction as well as smart radomes.