Hybrid multilayer textile composites reinforced with silver, carbon and para-aramid for electromagnetic interference shielding

In this study, a hybrid multilayer composite shielding material was developed, and the effects of material type, layer number, stacking sequence, and interfacial architecture on total shielding effectiveness (SET) were investigated. For this purpose, 20 preforms consisting of high-conductivity carbon woven fabrics (CF), polyester/viscose (PES/VIS) fabrics with Ag-coated PA conductive weft yarns, and dielectric Twaron (T) layers were fabricated using an epoxy matrix via the hand lay-up method. Among the samples, 4-layer structures (Samples 7 and 8) exhibited SE values of 46–79 dB, while 9-layer structures (Samples 19 and 20) showed stable performance of at least 53 dB across the X-band. Maximum SE values were obtained as 91.56 dB at 11.5 GHz and 91.03 dB at 9.02 GHz. Analyses revealed that 28–65% of incident electromagnetic energy was absorbed, 33–72% was reflected, and transmission was negligible. Positioning Twaron on the incident side resulted in a higher absorption coefficient, whereas a carbon-fronted configuration exhibited a higher reflection coefficient. Shielding performance is governed by a balance between reflection and absorption. The incident wave is partially reflected, while the remaining portion penetrates the structure and interacts with the conductive carbon layers and the Ag-grid PES/VIS layer. Dielectric and conduction-related losses, together with multiple internal reflections and interfacial interactions, may contribute to electromagnetic attenuation within the multilayer structure. Overall, composite thickness, material selection, stacking sequence, and structural design are important parameters influencing EMI shielding performance and the balance between absorption, reflection, and transmission.