Figure 3. The proposed tunable impedance metasurface.

(a) Schematic of the metasurface and enlarged half unit cell with dimensional parameters. The unit cell is enclosed by the pink dash rectangle. (b) The half unit cell with periodic boundary conditions is equivalent to the infinite board. The red arrow represents the current distribution with mirror symmetry. The half unit cell can be modeled as parallel resonant tanks in serial, and the boundary condition can be modeled as the transmission line.