Reconfigurable Metasurface Based on Shape Memory Alloy Actuators for Ultra‐Wideband RCS Reduction

Abstract Reconfigurable metasurfaces exhibit remarkable capabilities in suppressing radar scattering signatures, but their effectiveness is often constrained by a single modulation mechanism. This work proposes an ultra‐wideband radar cross section (RCS) reduction metasurface based on height‐tunable absorbing unit cells actuated by shape memory alloy (SMA) springs. This design integrates a three‐layer lossy absorber for broadband low‐frequency absorption with dynamic phase modulation of sub‐blocks, achieving frequency‐controllable scattering manipulation through phase cancellation. By electrically tuning the bias voltages applied to the SMA springs, the metasurface can switch among strong absorption, frequency‐tunable scattering, and ultra‐wideband RCS reduction states. Experimental results show a broadband high absorption in the range of 4–12 GHz, while height tuning of the SMA‐actuated elements enables frequency‐controllable RCS reduction from 16.1 to 36.3 GHz. In the integrated state, a superior 20 dB RCS reduction is achieved across 4.2–40 GHz. Moreover, the metasurface maintains robust performance under wide‐angle incidence and different polarizations, demonstrating great potential for adaptive scattering control and dynamic camouflage applications.