A Bionic Grooving All‐Cementitious‐Dielectric Metastructure with Unprecedented Wide‐Angle Broadband Electromagnetic Wave Absorption Properties

Abstract The absorption performance of electromagnetic (EM) wave absorbing materials deteriorates sharply at large incident angles, particularly at angles exceeding 50°. To overcome this challenge, this study proposes a bionic grooving all‐cementitious‐dielectric metastructure (ACDMS), yielding more than 34.6 GHz effective absorption bandwidth (EAB) over 0°–60° incident angles without any absorbing agent. The effects of structural design, geometric parameters, and incident angles on the EM response and absorption performance are investigated by numerical simulations and experimental characterizations. It is found that the ACDMS enables multiple absorption mechanisms under various incident angles, including electric field redistribution, multi‐axis interference, surface wave excitation, and multiple diffraction/scattering pathways. Experimental results demonstrate that at 60° incident angle, the absorption performance of the ACDMS even exceeds that at normal incidence, achieving a relative EAB of 163%, a ‐20 dB (99% absorption) bandwidth of 33.4 GHz, and a mean reflectivity of −23.4 dB in 1–40 GHz range. The RCS simulation and environmental testing across fluctuating humidity (40%–80%) and temperature (10–220 °C) exposures underscore the exceptional potential for practical applications and harsh environmental conditions. The combination of innovative absorption mechanisms, environmental adaptability and a convenient cement‐based manufacturing process establishes the ACDMS as a promising candidate for next‐generation EM wave absorbers.