This application provides a wireless power transfer unit, device, and method. The wireless power transfer unit includes a radiation source, a light-emitting body, a controller, and a metasurface. The radiation source is configured to emit an electromagnetic wave signal. The controller is configured to control the light-emitting body to provide light sources of different light intensities. The light-emitting body provides the light sources of different light intensities in response to control of the controller. The metasurface is configured to perform phase adjustment on the electromagnetic wave signal that is incident to the metasurface. Equivalent impedance of the metasurface varies with a change of the light intensity, so that an offset of a phase of the electromagnetic wave signal emitted through the metasurface also varies with the change of the light intensity.