Multifunctional meta-absorber for multispectral camouflage against infrared, radar, and microwave radiometric detection

The rapid advancement of integrated detection systems poses a severe threat to the survivability of high-value ground targets. However, conventional camouflage strategies typically focus on individual detection methods. As microwave radiometers are increasingly integrated into modern detection systems, existing strategies exhibit limitations in addressing the challenges posed by multispectral detection systems. Herein, a multifunctional meta-absorber is proposed, numerically and experimentally demonstrating integrated multispectral camouflage capabilities against infrared, radar, and microwave radiometric detection. The meta-absorber consists of an infrared shielding layer (IRSL) and a radar absorption-microwave emissivity layer (RAMEL). The IRSL is realized through a frequency-selective surface, achieving a low infrared emissivity of 0.334 while ensuring efficient microwave transmission. The RAMEL utilizes a multilayer stacked structure and is based on the ohmic loss mechanism, achieving over 90% broadband absorption in the 4.62–28.29 GHz. This absorption performance leads to a substantial reduction in the radar cross section, achieving a 10 dB reduction in the 4.38–21.18 GHz. More importantly, based on Kirchhoff’s law of thermal radiation, the meta-absorber employs its high microwave emissivity to minimize the brightness temperature contrast between metallic targets and the background, resulting in a 40.33% reduction in the average contrast. Characterized by low infrared emissivity, high absorptivity, high microwave emissivity, wide-angle stability, and polarization insensitivity, the proposed meta-absorber provides a viable solution for multispectral camouflage, enhancing the survivability of high-value ground targets.