Low-cost electromagnetic interference shielding using recycled aluminum foil composites

Abstract

Can household waste materials provide effective electromagnetic interference shielding at a fraction of commercial product costs? This research investigates the shielding effectiveness of composite materials fabricated from recycled aluminum foil sourced from post-consumer waste streams. The investigation examined layered composite structures containing five, ten, and fifteen aluminum foil layers bonded with polymer adhesives, measuring shielding performance across frequencies from 100 MHz to 3 GHz. Testing was conducted at the Wellington Institute of Technology electromagnetic compatibility laboratory from February through July 2024. Results demonstrated that recycled aluminum foil composites achieved shielding effectiveness ranging from 23.8 dB for five-layer configurations to 58.2 dB for fifteen-layer structures at 1 GHz test frequency. These values approach performance levels of commercial shielding products while reducing material costs by 65-78%. The fifteen-layer composite achieved 94.7% of the shielding effectiveness measured for commercial reference materials at equivalent thickness, suggesting viable substitution potential for non-critical applications. Statistical analysis of 847 individual measurements revealed consistent performance across samples fabricated from different aluminum foil sources, with coefficients of variation below 8.3% for all composite configurations. Frequency-dependent behavior showed increasing shielding effectiveness at higher frequencies, consistent with theoretical predictions for reflection-dominated shielding mechanisms. The cost-performance ratio favored recycled composites across all tested configurations, with the ten-layer variant offering optimal balance between shielding capability and material expenditure. These findings support the feasibility of recycled aluminum foil composites as economical alternatives to commercial shielding materials for applications including consumer electronics enclosures, cable shielding, and architectural electromagnetic protection. The research demonstrates that sustainable material sourcing need not compromise functional performance for electromagnetic compatibility applications.