scholarly journals Effect of moisture content on the electromagnetic shielding ability of non-conductive textile structures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sundaramoorthy Palanisamy ◽  
Veronika Tunakova ◽  
Jiri Militky ◽  
Jakub Wiener
Keyword(s):  
Electromagnetic Field ◽  
Moisture Content ◽  
Electromagnetic Shielding ◽  
The Body ◽  
Shielding Effectiveness ◽  
Electrically Conductive ◽  
Drying Time ◽  
Textile Materials ◽  
Conductive Textile ◽  
Electromagnetic Shielding Effectiveness

AbstractElectromagnetically shielding textile materials, especially in professional or ordinary clothing, are used to protect an implanted pacemaker in the body. Alternatively, traditional textiles are known for their non-conductivity and transparency to an electromagnetic field. The main goal of this work was to determine whether the high moisture content (sweat) of the traditional textile structure significantly affects the resulting ability of the material to shield the electromagnetic field. Specifically, whether sufficient wetting of the traditional textile material can increase its electrical conductivity to match the electrically conductive textiles determined for shielding of the electromagnetic field. In this study, cotton and polyester knitted fabric samples were used, and two liquid medias were applied to the samples to simulate human sweating. The experiment was designed to analyse the factors that have a significant effect on the shielding effectiveness that was measured according to ASTM D4935. The following factors have a significant effect on the electromagnetic shielding effectiveness of moisturised fabric: squeezing pressure, drying time and type of liquid media. Additionally, the increase of electromagnetic shielding was up to 1 dB at 1.5 GHz frequency at the highest level of artificial sweat moisturised sample.

scholarly journals Conductive textile structures and their contribution to electromagnetic shielding effectiveness

2020 ◽  
Vol 71 (05) ◽  
pp. 432-437
Author(s):  
Ion Razvan Radulescu ◽  
Lilioara Surdu ◽  
Bogdana Mitu ◽  
Cristian Morari ◽  
Marian Costea ◽  
...  
Keyword(s):  
Electromagnetic Compatibility ◽  
Modern Technology ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Frequency Range ◽  
Conductive Coatings ◽  
Tem Cell ◽  
Conductive Yarns ◽  
Conductive Textile ◽  
Electromagnetic Shielding Effectiveness

Fabrics for electromagnetic shielding are especially relevant in nowadays context, contributing to human’s protection and wellbeing and to proper functioning of electronic equipment, in relation to electromagnetic compatibility. Fabrics with electromagnetic shielding properties employ two main technologies, namely insertion of conductive yarns and application of conductive coatings. Magnetron sputtering is a modern technology to enable conductive coatings with thickness in the range of nanometers onto fabrics. This paper aims to analyze contribution of various conductive textile structures out of both fabrics with inserted conductive yarns and coatings to Electromagnetic shielding effectiveness (EMSE). EMSE was measured in the frequency range of 0.1–1000 MHz by using a TEM cell according to standard ASTM ES-07. Results show a gain of 10–25 dB when introducing silver yarns in warp/ weft direction, a variation of 5–35 dB between conductive yarns out of silver and stainless steel and an up to 12 dB gain out of thin copper coating by magnetron plasma onto the fabrics with inserted conductive yarns

scholarly journals Investigating electromagnetic shielding effectiveness of knitted fabrics made by barium titanate/polyester bicomponent yarn

2019 ◽  
Vol 14 ◽  
pp. 155892501983780
Author(s):  
Rumeysa Celen ◽  
Yusuf Ulcay
Keyword(s):  
Barium Titanate ◽  
Electronic Devices ◽  
Electromagnetic Shielding ◽  
Shielding Effectiveness ◽  
Knitted Fabrics ◽  
Mechanical And Electrical Properties ◽  
Fabric Density ◽  
Conductive Textile ◽  
Electromagnetic Pollution ◽  
Electromagnetic Shielding Effectiveness

Electromagnetic pollution is a problem that damages all creatures and electronic devices. Most of the electronic devices we use at homes emit electromagnetic radiation. Conductive textile surfaces are used for electromagnetic shielding applications. However, to provide electromagnetic shielding, there has not been any study on the bicomponent fiber production with barium titanate. For this purpose, in this study, bicomponent yarns were produced using three different adding ratios of barium titanate. The mechanical and electrical properties of the yarns were investigated. Knitted fabrics were produced from bicomponent yarns with two different fabric densities using a circular knitting machine. The effects of the additive ratio and the fabric density on the effectiveness of the electromagnetic shielding were also investigated. The fabric with the highest content of the barium titanate and greater fabric density showed the highest shielding effectiveness, reaching 25.95 dB at 0.02 GHz.

scholarly journals Electromagnetic Wave Shielding Properties of Amorphous Metallic Fiber-Reinforced High-Strength Concrete Using Waveguides

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7052
Author(s):  
Sangkyu Lee ◽  
Gyuyong Kim ◽  
Hongseop Kim ◽  
Minjae Son ◽  
Yaechan Lee ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Moisture Content ◽  
High Strength Concrete ◽  
High Strength ◽  
Electromagnetic Shielding ◽  
Steel Fibers ◽  
Shielding Effectiveness ◽  
Strength Concrete ◽  
Metallic Fibers ◽  
Electromagnetic Shielding Effectiveness

In this study, high-strength concrete containing hooked-end steel or amorphous metallic fibers was fabricated, and the electrical conductivity and electromagnetic shielding effectiveness were evaluated after 28 and 208 days based on considerations of the influences of the moisture content. Amorphous metallic fibers, which have the same length and length/equivalent diameter ratio as hooked-end steel fibers, were favored for the formation of a conductive network because they can be added in large quantities owing to their low densities. These fibers have a large specific surface area as thin plates. The electromagnetic shielding effectiveness clearly improved as the electrical conductivity increased, and it can be expected that the shielding effectiveness will approach the saturation level when the fiber volume fraction of amorphous metallic fibers exceeds 0.5 vol.%. Meanwhile, it is necessary to reduce the amount of moisture to conservatively evaluate the electromagnetic shielding performance. In particular, when 0.5 vol.% of amorphous metallic fibers was added, a shielding effectiveness of >80 dB (based on a thickness of 300 mm) was achieved at a low moisture content after 208 days. Similar to the electrical conductivity, excellent shielding effectiveness can be expected from amorphous metallic fibers at low contents compared to that provided by hooked-end steel fibers.

Analyses on the Manufacture and Physical Properties of Electromagnetic Shielding/ Far Infrared Ray Nonwoven

2010 ◽  
Vol 97-101 ◽  
pp. 1790-1793
Author(s):  
Jia Horng Lin ◽  
Yu Tien Huang ◽  
Chin Mei Lin ◽  
Yi Chang Yang ◽  
Chien Teng Hsieh ◽  
...  
Keyword(s):  
Physical Properties ◽  
Far Infrared ◽  
Electromagnetic Shielding ◽  
Breaking Force ◽  
Shielding Effectiveness ◽  
Machine Direction ◽  
Tear Strength ◽  
Burst Strength ◽  
Far Infrared Ray ◽  
Electromagnetic Shielding Effectiveness

According to the results, when low melting polyester fiber increased to be 20%, the electromagnetic shielding/ far infrared ray nonwoven obtained the optimum burst strength, maximum breaking force and maximum tear strength, and they were as follows: burst strength was 4.2 kgf/cm2; maximum breaking force was 153.59 N in the cross machine direction and 70.80 N in the machine direction; maximum tear strength was 215.77 N in cross machine direction and 117.07 N in machine direction; and optimum electromagnetic shielding effectiveness (EMSE) was 45 dB.

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