Broadband radar absorbing metamaterial based on Al @SiO₂ conductive composite film

Artificially designed metamaterial structures can manipulate electromagnetic waves, endowing them with exotic physical properties that are not found in natural materials, such as negative refractive index, superlens, and inverse Doppler effect. These characteristics are widely applied in various engineering and military applications. Due to increasingly complex application environments and innovation in radar detection technology, the combination of broadband absorption performance under thin thickness and efficient preparation methods at low cost is often the focus of research on new generation stealth materials. Here, we propose Al@SiO₂ composite conductive film metamaterial (Al@SiO₂ CCFM) to achieve wideband absorption of electromagnetic waves. This metamaterial structure combines two resonant units, resulting in three absorption bands in the absorption curve. The results show that the absorption rate of the metamaterial is above 90% in the frequency range of 10.6 GHz to 26.0 GHz. The resonance mechanism between multiple structures is a prerequisite for achieving wideband absorption. The materials Al and SiO₂ used in Al@SiO₂ CCFM are inexpensive and abundant, and the fabrication method is simple. Therefore, they hold great potential for large-scale applications in the multispectral stealth and electromagnetic shielding field.