Angle-Sensitive Metagratings for Bi-Functional Anomalous Reflection: Design and Experiment

Metagratings (MGs), constructed from sparsely arranged unit cells with tailored structures, are known for their high efficiency in wavefront manipulation, even at large incident angles. However, conventional passive MGs are generally limited to interacting with waves from a single angle at a specific frequency. In this work, a design for passive dual-angle-sensitive MGs (PDS-MGs) composed of unit cells with angular sensitivity is proposed, which exhibit distinct responses to two incident waves with different directions. By modulating the load impedance densities of the unit cells at two specific incident angles, PDS-MGs can achieve distinct energy distributions across different diffraction orders within the same geometrical configuration. To validate this approach, a proof-of-concept PDS-MG was constructed and tested, demonstrating anomalous reflection for waves incident at 0° and 25.7°, respectively. Simulation results reveal that the designed PDS-MG maintains a reflection efficiency of at least 90% in both cases, and experimental data show close alignment with these simulations. Capable of independently configuring functionalities for varying angles of incidence, PDS-MGs exhibit broad application potential in areas, such as angle sensors, displacement sensors, and intelligent reflective surfaces.