Computation Model of Shielding Effectiveness of Symmetric Partial for Anti-Electromagnetic Radiation Garment

Abstract

Abstract-Current shielding effectiveness (SE) of electromagnetic shielding (EMS) fabric is tested in the plane state, the testing results are difficult to describe the shielding effect of a garment in a curve surface state after manufactured by the fabric. To solve this problem, this study proposes a new SE computation model of the EMS fabric based on a SE vector. The model can calculate a theoretical SE value of the EMS fabric in the curve surface state. A number of factors which determine the SE of the fabric with a curve surface are analyzed according to the principle of the reflection and transmission of the electromagnetic wave. This study also gives a new argument that the curve fabric can be divided into many micro-planes and the fabric SE is considered as a vector. And then a computation model of the SE of the curve fabric is constructed. The detail of computation is deduced, and an application example is given. Results of experiments and analyses show that the method is scientific and correct, and the error between the computation SE value and the testing SE value of the local garment is less than 3%. The model provides a new way to calculate the SE of the EMS fabric with symmetric curved surface.

Electromagnetic Shielding Effectiveness of Woven Fabrics with High Electrical Conductivity: Complete Derivation and Verification of Analytical Model

“…A similar equation can be also found in [4,21,22,24]. The calculation of reflection loss R foil corresponds to the copper conductivity value, e.g., σ Cu = 5.82 × 10 7 S/m [32], 5.7 × 10 7 S/m [37], or 5.85 × 10 7 S/m [38], which depends on the purity and the production method of copper.…”

“…Many research papers describe SE evaluation from different perspectives, i.e., measurement techniques [1,2,3,4,5,6,7], composition of materials [8,9,10,11,12,13,14,15,16,17], influence of washing/drying cycles on values of SE of fabrics [18,19,20], or calculation of SE [4,21,22,23,24,25,26,27,28,29,30,31]. SE measurement is commonly performed by a coaxial transmission line method specified in ASTM 4935-10 [1,2,3,4,6,8,9,10,12,14,17,18] by measuring the insertion loss with a dual transverse electromagnetic (TEM) cell [3,5], or by measurement in a free space, shielding box, or shielding room with receiving and transmitting antennas [7,15,19,20].…”

“…SE measurement is commonly performed by a coaxial transmission line method specified in ASTM 4935-10 [1,2,3,4,6,8,9,10,12,14,17,18] by measuring the insertion loss with a dual transverse electromagnetic (TEM) cell [3,5], or by measurement in a free space, shielding box, or shielding room with receiving and transmitting antennas [7,15,19,20]. The papers which focus on measurement techniques of various electrically conductive fabrics usually present basic equations for SE calculation [4,21,22,23,24,25,26,27,28] (SI units are used in all formulas unless otherwise stated) as shown in Equation (1). $SE=20\cdot {\log }_{10}\left|\frac{E_i}{E_t}\right|=20\cdot {\log }_{10}\left|\frac{H_i}{H_t}\right|=10\cdot {\log }_{10}\left|\frac{P_i}{P_t}\right|=R+A+B$ where E i , H i , and P i are the electric field intensity, magnetic field intensity, and power without the presence of tested material (incident electromagnetic field on the tested material), respectively, E t , H t , and P t are the same physical quantities with the presence of tested material (transmitted electromagnetic field measured behind the tested material), R is the reflection loss, A is the absorption loss, and B is multiple reflections.…”

Electromagnetic Shielding Properties of Knitted Fabric Made from Polyamide Threads Coated with Silver

“…that radiate EM energy in different frequency ranges aims to minimise the possibility of interference with radio and wired communications. The lifespan and efficiency of electronic devices can be increased by their protection against electromagnetic interference [ 1 , 2 , 3 , 4 , 5 , 6 ].…”

Virtual metal model for fast computation of shielding effectiveness of blended electromagnetic interference shielding fabric

“…However, currently the study about the SE of the blended EMI shielding fabric is mainly focuses on the model construction [16], SE variation analysis [17][18][19], SE testing method [20][21][22], fabric performance testing [23][24][25][26], and the development of the EMI shielding fabric [27][28][29]. In those studies, the SE of fabric was obtained by experiments; there were not a computation model and functions.…”