A Wideband Electrically Tunable Metasurface Absorber for Surface Waves

In this paper, an electrically tunable metasurface for surface-wave absorption was proposed, featuring a wideband and wide absorption range. It is composed of an array of tunable unit cells and biasing networks. PIN diodes are integrated into the unit cell as tunable devices, and their controlling effects on the cell’s absorption properties are analyzed through simulations. The results show that the absorption ranges from 8.7% to 94.8% when the forward biasing voltage for the diodes increases from 0 to 0.6 V. The frequency range with 20%-80% absorption is from 4.95 to 5.42 GHz, corresponding to a fractal bandwidth of 9.1%. This metasurface can potentially be developed for more advanced applications, such as nonlinear absorption. As an example, a surface-wave power sensing module is proposed. It is expected that by combining the module and the tunable metasurface, a power dependency of surface-wave absorption can be further achieved.