Multi-layer cement composites for absorption-dominant electromagnetic interference shielding with recycled carbon fibers

Abstract

This study examines the electrical conductivity and electromagnetic interference (EMI) shielding performance of cement composites incorporating various combinations of carbon fiber (CF) and recycled carbon fiber (rCF) with lengths of 6 mm and 12 mm. The composites were evaluated for their electrical properties and EMI shielding effectiveness, including reflection, absorption, and average power coefficients, across the C-band (4.0-8.2 GHz) and X-band (8.2-12.4 GHz) frequency ranges. In addition, the influence of multi-layer configurations was investigated to enhance absorption-dominant EMI shielding by promoting internal multiple reflections within the composite structure. The enhanced likelihood of repeated internal reflections within the layered structures led to an absorption-dominant EMI shielding behavior, increasing the absorption contribution by 17.2 % and 15.3 %, respectively, while maintaining a comparable total shielding effectiveness. The results demonstrate that the incorporation of both CF and rCF in multilayered structures significantly improves absorption performance, confirming the potential of these composites for absorption-focused EMI shielding applications.