Space‐Time‐Coding Metasurfaces Enabling Programmable Range‐Angle‐Dependent Energy Auto‐Scanning

ABSTRACT Dynamic regulation of electromagnetic energy distribution in space plays a pivotal role in fields like radar detection and wireless communications. However, the state‐of‐the‐art solution based on antenna array requires transmit/receive (T/R) modules per radiating element, causing exponential cost scaling and high power consumption. While reconfigurable metasurfaces have been demonstrated to enable real‐time beam scanning in prior works, they can only adjust beam direction and lack the ability to tune energy distribution across different distances. This paper presents a theory for space‐time‐coding metasurface (STCM) enabled spatiotemporal energy auto‐scanning. By applying identical time‐varying modulation signals with time delays to each column of the STCM, the reflected energy distribution can be made angle‐range‐time‐dependent. Based on this principle, a novel positioning system is designed, enabling decoupled estimation of a target's angle and distance relative to the metasurface. For experimental validation, a 2‐bit metasurface prototype is fabricated and tested. Experimental results align with theoretical analysis, confirming STCM's functional efficacy and deployment potential for applications in radar detection, wireless communications, and related fields.