Spin-selective reconfigurable reflective metamaterial based on shape memory alloy

This paper proposes a spin-selective reconfigurable reflective metamaterial based on shape memory alloy (SMA). The metamaterial unit consists of copper foil and two pieces of SMA, which utilizes the temperature-dependent characteristics of SMA to achieve dynamic control of electromagnetic wave through morphological transformation. As the temperature increases, the unit structure gradually bends from being attached to the dielectric layer to forming a semicircle, exhibiting spin-selective reflection of circularly polarization within the frequency range from 4.9 GHz to 5.5 GHz. Furthermore, by constructing a metamaterial array and using FPGA to generate voltage signal for precise control of the local temperature of each unit, flexible tuning of functionality is realized to meet various application demand. Compared with traditional reconfigurable metamaterials, the designed metamaterial offers temperature-adaptive spin control capabilities, providing a novel implementation pathway for the integration of SMA with electromagnetic metamaterials, and promises broad application prospects in areas such as beam control and wireless communication.