The microwave absorption properties variation with temperature of RF/SiO₂ and improved microwave absorption by periodic structure

With the widespread application of radar detection systems in the military field, the development of radar stealth technology can effectively reduce the characteristic signals of targets, which was of great significance for the protection of important military targets. In this paper, the resorcinol/formaldehyde (RF) reinforced silica aerogel (RF/SiO₂) was synthesized successfully. The RF was introduced into the sol/gel technology to build a porous skeleton, and the SiO₂ aerogel was prepared by atmospheric pressure drying. The RF/SiO₂ aerogel was then heat treated, and the microstructure and physical properties of the RF/SiO₂ aerogel before and after heat treatment were characterized to study the influence of the heat treatment temperatures on the RF/SiO₂ aerogel. With the increase of the heat treatment temperature, its electromagnetic wave absorption performance had been significantly improved. When the heat treatment temperature reached 1500 ℃, the RF/SiO₂ aerogel possessed a minimum reflection loss of − 36.42 dB at 1.95 mm and an effective bandwidth of 2.94 GHz at 2.00 mm within the radar band of 8.00–12.00 GHz. In addition, this paper used CST software to optimize and design the periodic structure of metamaterial based on the RF/SiO₂ aerogel. The optimization design of the patch size and substrate thickness on the substrate surface provided a reference for the future application of this material in specific radar stealth fields.