Reconfigurable magnetic near-field distributions based on the coding metasurfaces in MHz band

Magnetic near-field control has attracted extensive attention and have a wide range of applications in filters, sensors, and energy-transfer devices. Coding metamaterial has the convenience of miniaturization and integration, which not only provides a bridge between physics and information science, but also exploits a whole new perspective for magnetic near-field control. In this work, we theoretically propose and experimentally verify that the coding metasurface can realize the reconfigurable magnetic near-field distributions. By adjusting the digital voltage signals which drive the resonant units of metasurface, capacitance of the resonator can be dynamically controlled, thus the dynamic modulation of magnetic near-field distribution can be achieved. Specially, this magnetic near-field control can be explained with the help of coupled mode theory and coherent superposition method. Moreover, simulated annealing algorithm is employed to determine working frequency of the whole modulation system, which can avoid time-consuming frequency scanning process. The experimental results are in good agreement with the calculated results. This work reveals the significant potential of coding metasurface for the experimental study of the magnetic near-field control and promotes the use of metasurface for numerous integrated functional devices.