The electromagnetic shielding effectiveness of laminated fabrics using electronic printing

This paper describes the development of laminated fabrics that contain a silver grid for electromagnetic shielding (EMS) applications. The silver grid was constructed with 0.3, 0.4, and 0.5 mm wire diameters and spacings. To reduce material costs, a solvent-based polytetrafluoroethylene (PTFE) film, cotton woven fabric, and conductive silver paste were used to fabricate a cost-effective EMS conductive laminated fabric successfully. Using a coaxial transmission line holder, the electromagnetic shielding effectiveness (EMSE) of various conductive laminated fabrics was measured in the 30 to 3000 MHz frequency range. The variation in the EMSE of the conductive networks with different grid shapes, grid densities, fineness values for the conductive lines, and concentrations of the silver paste on the PTFE films was evaluated. Based on optical microscopy observations and analysis, it was found that the conductive silver paste that was diluted by a high boiling point solvent comprising a mixed dibasic acid ester (DBE) could be printed on the PTFE film using a 300-mesh screen to obtain a clear and complete mesh wire structure that was easy to coat. The results indicated that the proposed conductive laminated fabrics with the 0.3 mm silver wire dimension and spacing had a higher EMSE and electrical conductivity than those of the 0.4 and 0.5 mm wire dimensions and spacings. The results also showed that the fabrics with a 0.3 mm wire diameter and spacing with DBE dilution had a slightly lower EMSE and electrical conductivity than those of the bare PTFE films with a 0.3 mm wire diameter and spacing in the 120 to 2450 MHz frequency range. The conductive laminated fabrics with a 0.3 mm wire diameter and spacing silver electronic coating could be used for electromagnetic interference shielding applications. The conductive silver-laminated woven fabric could also be applied to curtains, wall coverings, bedspread sets, maternity clothes, work bibs, microwave ovens, induction cookers, protective clothing, and antielectromagnetic mobile phone sets.