Photonic Frequency‐Sensing Adaptive Microwave Metasurface

Frequency‐selective metasurface (FSM) plays a pivotal role in adaptive control of electromagnetic waves in radar, aerospace, and wireless communication. Conventional tunable metasurfaces rely on external electronic circuits or antenna front ends to sense and adjust their spectral states, which restricts system compactness and autonomy. Here, we demonstrate a photonic frequency‐sensing adaptive FSM that eliminates the need for antennas by integrating frequency perception and spectral reconfiguration. The device directly receives spatial microwave signals through a thin‐film lithium‐niobate chip and performs frequency discrimination in the optical domain, driving closed‐loop tuning of the metasurface response. A proof‐of‐concept demonstration confirms adaptive reconfiguration in absorption modes under frequency‐unknown excitations. By combining photonic frequency sensing with adaptive metasurface control in a unified proof‐of‐concept platform, this work suggests a compact route toward future integrated electromagnetic systems for communication, sensing, and shielding applications.