Determination of electromagnetic shielding performance of hybrid yarn knitted fabrics with anechoic chamber method

The electromagnetic shielding effectiveness (SE) of various weft-knitted fabrics made of hybrid yarns is investigated by considering the anisotropy of the structures, which has not been analyzed in previous studies. The anechoic chamber with aperture method at different polarizations of electromagnetic waves within the frequency range of 30 MHz and 9.93 GHz is used to determine the SE of knitted fabrics manufactured on a circular weft knitting machine from siro-spun and siro core-spun yarns without and with a metal core. The results show that SE depends on the orientation of the fibers within the structure regarding the direction of the electrical field in addition to parameters such as metal content, loop length and frequency; these results can be used to outline the basic points in determining a knit structure with desired SE.