Effect of needle loops on shielding effectiveness of electromagnetic shielding knitted fabrics

Knitted electromagnetic shielding fabric is widely used for its excellent extensibility and permeability. However, the influence law and mechanism of the effect of needle loops on the shielding effectiveness of fabrics is still unclear. In this paper, we designed five kinds of knitted fabrics. They are plain single jersey, ‘1 × 1’ rib knitted fabric, ‘2 × 2’ rib knitted fabric, interlock knitted fabric, and full Milano structure. The shielding effectiveness adopts the flange coaxial test. Based on the electromagnetic theory principle, the influence law and mechanism of needle loop arrangement form, needle loop length, metal material, and metal amount on the shielding effectiveness of knitted fabrics were analyzed. Therefore, it can be concluded that the arrangement of needle loops dramatically influences the frequency band and shielding performance of knitted fabrics. When there is fewer intermeshing points of needle loops, the less is the shielding effectiveness of the fabric. The needle loop’s length mainly affects the shielding effectiveness of knitted fabric. The small needle loop length has great shielding effectiveness on knitted fabric. Metallic yarns with high amounts and low -resistance are beneficial for improving the shielding effect of the clothing. It provides a reference for the design, production, and related research of electromagnetic shielding knitted fabrics.