Rapid computation model for accurate evaluation of electromagnetic interference shielding effectiveness of fabric with hole based on equivalent coefficient
Abstract:Though electromagnetic interference (EMI) shielding fabric with rectangular hole has wide application in various fields, there is not a mature approach to calculate its shielding effectiveness (SE) at present. This paper constructs a rapid computation model of the SE of the EMI shielding fabric with hole based on equivalent coefficient. Firstly, the rectangular hole characteristic is analyzed and a structure model of the rectangular hole under the consideration of the hole edge characteristic is described. The… Show more
“…The larger the hole area and the longer the hole seam lead to more leakage of the electromagnetic waves. 28 We call the area with more seams, openings, buttons, slide fasteners and other accessories as the leakage area, and the area with less seams, openings, and accessories as the normal area. Let the overall area is A and the area of the hole is S, the transmission coefficient Th of the electromagnetic wave at the hole can be expressed as 28 Figure 10.Schematic diagram of the leakage area and normal area.…”
Section: Results and Analysismentioning
confidence: 99%
“…28 We call the area with more seams, openings, buttons, slide fasteners and other accessories as the leakage area, and the area with less seams, openings, and accessories as the normal area. Let the overall area is A and the area of the hole is S, the transmission coefficient Th of the electromagnetic wave at the hole can be expressed as 28 Figure 10.Schematic diagram of the leakage area and normal area.…”
There is no perfect method to test and evaluate electromagnetic shielding (EMS) clothing up to now. The main reason is that the influence laws of the emission source parameters and the test position on the shielding effectiveness (SE) of the EMS clothing has not been clarified. In this paper, the SE of the EMS clothing is tested using a semi anechoic chamber in the frequency range of 1–18 GHz. The variation of the SE of the clothing is explored when the emission source parameters and the test positions are different. It is found that the SE of the EMS clothing decreases obviously with the increase of the testing distance, and the decline degrees are different with different frequencies. The decline trend slows down and approaches stability as the distance increases to a certain extent. The influence of the emission source angle on the SE is closely related to the frequency and positive or negative effects are produced at different frequency points. The SE are low when the test points are in the leakage areas with seams and openings, and the SE are high in the normal area. Under certain conditions, the measured SE of the clothing is close to zero or even less than zero. That is, a dangerous frequency point is formed. The mechanism of the above-mentioned laws is analyzed, and a new multi-index composite evaluation method is proposed to scientifically evaluate the EMS clothing based on the comprehensive consideration of the influencing factors. This research has great significance to promote the scientific test, evaluation and relevant standard formulation of the EMS clothing, and provides a reference role for the design and production of the EMS clothing.
“…The larger the hole area and the longer the hole seam lead to more leakage of the electromagnetic waves. 28 We call the area with more seams, openings, buttons, slide fasteners and other accessories as the leakage area, and the area with less seams, openings, and accessories as the normal area. Let the overall area is A and the area of the hole is S, the transmission coefficient Th of the electromagnetic wave at the hole can be expressed as 28 Figure 10.Schematic diagram of the leakage area and normal area.…”
Section: Results and Analysismentioning
confidence: 99%
“…28 We call the area with more seams, openings, buttons, slide fasteners and other accessories as the leakage area, and the area with less seams, openings, and accessories as the normal area. Let the overall area is A and the area of the hole is S, the transmission coefficient Th of the electromagnetic wave at the hole can be expressed as 28 Figure 10.Schematic diagram of the leakage area and normal area.…”
There is no perfect method to test and evaluate electromagnetic shielding (EMS) clothing up to now. The main reason is that the influence laws of the emission source parameters and the test position on the shielding effectiveness (SE) of the EMS clothing has not been clarified. In this paper, the SE of the EMS clothing is tested using a semi anechoic chamber in the frequency range of 1–18 GHz. The variation of the SE of the clothing is explored when the emission source parameters and the test positions are different. It is found that the SE of the EMS clothing decreases obviously with the increase of the testing distance, and the decline degrees are different with different frequencies. The decline trend slows down and approaches stability as the distance increases to a certain extent. The influence of the emission source angle on the SE is closely related to the frequency and positive or negative effects are produced at different frequency points. The SE are low when the test points are in the leakage areas with seams and openings, and the SE are high in the normal area. Under certain conditions, the measured SE of the clothing is close to zero or even less than zero. That is, a dangerous frequency point is formed. The mechanism of the above-mentioned laws is analyzed, and a new multi-index composite evaluation method is proposed to scientifically evaluate the EMS clothing based on the comprehensive consideration of the influencing factors. This research has great significance to promote the scientific test, evaluation and relevant standard formulation of the EMS clothing, and provides a reference role for the design and production of the EMS clothing.
“…According to EMS theory, Wang and Liu 94 set the hole area as S , the short side as a , the long side as b , and the total area as A for the rectangular hole on EMSF with holes, and established the theoretical calculation model of EMSF SE with holes: …”
Section: Study On the Structure Model Of Electromagnetic Shielding Fa...mentioning
With the widespread adoption of electronic technology, electromagnetic (EM) interference has become increasingly severe, adversely affecting the normal operation of electronic systems and posing significant threats to human health. EM shielding materials can effectively suppress various EM waves and EM interference generated through space by improving the EM compatibility of electronic systems and electronic devices. Recently, fiber-structure materials have been widely used for EM shielding due to their softness, thinness, and superior shielding efficiency. Therefore, this paper focused on fiber-based EM shielding materials, discussed the basic principles of EM shielding, the types of EM shielding fibers, the efficiency factors of EM shielding fabrics, and presented prospects for the future development of such materials.
“…Liu et al (2016) and Liu et al (2017a) used the finite-difference time-domain method to analyze the calculation method of the SE of the clothing fabric, which provides a reference for the overall evaluation of the SE of the EMS clothing. Liu et al (2015a) and Wang et al (2015) further discussed the influence of the holes on the SE of the clothing fabric and pointed out the influence rule of the holes on the SE of the EMS clothing fabric in plane state. Other researches on the EMS clothing are mainly focused on the shielding performance, such as the shielding fiber performance (Vojtech and Neruda, 2013;Duan et al, 2019), identification and analysis of the shielding fiber in fabric (Liu et al, 2017b;Wang et al, 2017), influencing factors of the SE and the reflection performance (Li et al, 2019), the SE prediction (Yang et al, 2019) and the model construction (Wang et al, 2014;Liu et al, 2015b).…”
PurposeThe change rules of the shielding effectiveness (SE) of the sleeve has not been clarified, which leads to the lack of the basis for the design, manufacture and evaluation of the electromagnetic shielding (EMS) clothing.Design/methodology/approachAccording to a simplified analysis model, a series of sleeve samples with different fabrics and styles are designed and manufactured. The SE of the sleeve is tested with the proposed special test method in a semi-anechoic chamber to analyze the influence of different factors on the SE of the sleeve.FindingsThe SE is greatly reduced about 60–90% after the fabric is manufactured into the sleeve. The larger the sleeve length is, the higher the peak value of the SE is. When the sleeve length is low, the SE value is easy to appear negative. As the cuff circumference increases, the SE of the sleeve will change with the frequency band. The influence of the cuff style on the SE of the sleeve mainly depends on the cuff width and style. The larger the cuff width is, the lower the overall SE of the sleeve is. The more wrinkles there are at the cuff, the better the SE of the sleeve is.Originality/valueOur results provide a reference for the design, production and evaluation of the sleeve and the whole EMS clothing.
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