The Anomalous Reflection and Refraction of Metasurface in the View of Solar Concentrators

Solar thermal power generation integrates photothermal conversion power generation and low-cost, large-scale heat storage, which is the primary support for constructing a green power system with new energy as the main body. The concentrating system is a critical component of solar thermal power plants. However, traditional concentrators are bulky and require complex solar tracking systems, limiting the reduction of solar thermal power costs. The metasurface can freely regulate electromagnetic waves and can be used in the field of solar concentrators, making it suitable for developing lightweight, low-cost, tracking-free solar concentrators and being a transformative technological solution in the energy field. Considering that the solar position varies with respect to a fixed planar metasurface concentrator, in this paper, we investigate the anomalous reflection and refraction phenomenon on the metasurface when the incident plane is not parallel to the direction of the static phase gradient of the metasurface. Utilizing vector equation derivation, Matlab calculation, and full-wave simulation based on the Finite difference-time domain (FDTD) method, all found the new property of the metasurface: its refracted ray, reflected ray, and normal are in the same plane, which is called the exit plane, and is at a certain angle to the incident plane.