Enhancing the performance of high-efficiency electromagnetic shielding via controlling the thickness of balsa wood in the FP cavity structure

The issue of electromagnetic pollution is becoming increasingly severe in the contemporary information age. Thus, the development of high-efficiency, lightweight, and environmentally friendly EMI shielding materials is of great significance. In this study, magnetron sputtering technology was utilized to deposit a Cu metal nanofilm on the surface of balsa wood, and a Fabry–Perot (FP) cavity structure with wood as the substrate was constructed. By adjusting the thickness of the wood layer, the shielding performance of the material against electromagnetic interference was optimized. The results show that when the total thickness of the coating is controlled at 100 nm and the thickness of the wood is 8 mm, the material exhibits the best electromagnetic interference shielding efficiency, reaching 33.92 dB. This wood-based composite material not only has excellent EMI shielding performance but also features lightweight properties. Moreover, research has revealed its potential infrared stealth capabilities. In addition, experiments have verified the feasibility of this material in EMI shielding within common frequency bands and in practical applications. It is expected to be widely used in multiple shielding fields such as the protection of electronic devices and military stealth.