Metasurface‐Integrated 3D Metastructures for Ultra‐Broadband Electromagnetic Stealth

ABSTRACT Developing electromagnetic absorbing structures that combine ultra‐broadband and lightweight characteristics is of significance in microwave engineering and stealth technology. A 2D metasurface‐3D metastructure composite design is proposed to construct a Resonator‐Gyroid Synergistic Metamaterial (R‐GSM). This structure integrates a 2D indium tin oxide (ITO) array with a 3D carbon‐based gradient Gyroid network. By coupling the low‐frequency resonance of the 2D units with the high‐frequency impedance matching and multiple scattering of the 3D structure, a continuous energy dissipation path is established. The results indicate that the R‐GSM mitigates the low‐frequency thickness constraints dictated by the traditional quarter‐wavelength resonance model. A prototype with a thickness of 15 mm (0.25 g/cm 2 ) demonstrates ultra‐broadband absorption from 2.4 to 40.0 GHz. Furthermore, by scaling the thickness to 20 mm (0.32 g/cm 2 ), it achieves a broad absorption bandwidth of 182.8% (1.8–40.0 GHz, reflection loss < −10 dB), approaching theoretical limits. It also exhibits excellent wide‐angle incidence stability and polarization insensitivity, with measurements closely matching multiphysics simulations. Radar cross‐section (RCS) evaluations demonstrate that this structure can be conformally integrated with curved surfaces, significantly reducing the scattering signatures of targets. The multi‐dimensional heterogeneous integration strategy provides a reliable design approach for developing lightweight and ultra‐broadband electromagnetic stealth structures.