Effect and mechanism of the opening area on the shielding effectiveness of an electromagnetic shielding garment

The opening area has an important effect on the overall protective performance of electromagnetic shielding (EMS) garments, but its mechanism and influencing laws are not clear. In this paper, a semi-anechoic chamber is adopted to construct a testing system, and a tying and covering method is proposed to test the shielding effectiveness (SE) of the garment with different parameters of opening area. Combined with electromagnetic theory, experimental results are analyzed, and influence laws and mechanisms of the opening area on the overall SE of the garment are discovered. Based on this, some new ideas for designing and evaluating EMS garment are proposed. We conclude that the opening area has a reducing effect on the SE of the garment in the frequency range of 1–3 GHz. The larger the size of the opening area, the more obvious the effect is. When reaching a certain size, the value of overall SE reaches zero or can even be negative, resulting in a significant decrease in the protective performance of the garment or even complete loss of its protective effect. The distance between the opening and the test point has a significant influence on the SE of the garment: the closer the distance, the greater the influence is. The opening closest to the testing point has a decisive effect on the overall SE of the garment. The style of opening area has a significant influence on the SE of the garment: pleated or inclined shape can improve the SE. Based on the above rules, a multi-index comprehensive weighted testing evaluation method for an EMS garment that fully considers the influence proportion of each opening is proposed, providing a scientific reference for the design, production, testing, and evaluation of EMS garments.