| Electromagnetic textiles growing concern because of it has both excellent electromagnetic performance and the soft, light-weight and other characteristics of textile material. It has become an important part of high-performance electromagnetic materials now. Therefore, research electromagnetic wave propagation in the fabric based on electromagnetic field theory become a very important research topic. The purpose of this study is to achieve the three-dimensional fabric structure of electromagnetic simulation, quantitative calculation of the influence of fabric structure, material properties and the electromagnetic wave incident angle on the electromagnetic performance of the fabric. And put forward a kind of numerical calculation method to extract ideal permittivity distribution of absorbing fabric, which contribute to lay the foundation to realize electromagnetic textile digital design.Firstly, measure the permittivity distribution of ordinary fabric in 1Hz-IOMHz range, using the Debye model and its extension model to nonlinear fitting the permittivity of fabric, and use the NRW method to quantitatively calculate the transmission characteristics of electromagnetic wave in the fabric. The results show that the permittivity of ordinary fabric rapid decreases within the range 1-100Hz to stabilize, close to the permittivity of the air; ordinary textile materials belong Debye type dispersion material, and Debye extension model can well describe the permittivity distribution of ordinary fabric; Almost all electromagnetic waves through the fabric, the loss rate of the electromagnetic wave is only about 10-8.Secondly, the use of TexGen software to build three-dimensional structure model of plain,2/1 twill and 5/3 satin weave fabric, and get one-sided laminated fabric, symmetric double-sided and asymmetric double-sided fabric model, which is formed on coating or lamination process. Above all in preparation electromagnetic simulation for fabric.Thirdly, the establishment of electromagnetic shielding fabric simulation model, in NRW method validation the reliability of the shielding simulation model, simulation calculation and analysis the fabric conductivity, electromagnetic wave incident angle, fabric density and fabric layers to the shielding effectiveness of fabric. The results show that the fabric electromagnetic shielding effectiveness increases with the conductivity significantly increased, when the conductivity is greater than 500S/m, shielding effectiveness appears dispersion characteristics; Fabric density are the key factor affecting shielding effectiveness; The first layer of laminated fabric plays a main role in the electromagnetic wave reflection loss.Finally, the absorbing fabric simulation model is set up, with TLM method and actual measurement results verify the feasibility of the absorbing fabric simulation model, discuss the unit length, thickness, weave of fabric influence on absorbing performance of the fabric, and further analysis of the relationship between fabric absorbing performance and electromagnetic fields, what’s more, a kind of numerical calculation method for extracting the fabric ideal permittivity distribution is proposed. The results show that the fabric unit length and thickness are important factors affecting the performance of the absorbing fabric; Internal resistance loss type absorbing fabric under the effect of electromagnetic wave will form the strong electric field distribution is consistent with the current direction, magnetic field perpendicular to the electric field, but the field is small; The same fabric structure will appear a kind and above of ideal combination of permittivity, wherein the permittivity of air as the origin, the real materials, which is closest to the origin is the ideal permittivity.
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