Measurement And Calculation Of Dielectric Constant Of Metal - Containing Yarns

Metal fiber is a new kind of high performance fiber, which has the properties of the metal, such as heat conduction, electric conductivity, and also has the properties of the common fiber, such as softness, spinnability and so on. The metal fiber yarn is made of common fiber and metal fiber. At present, the metal fiber yarn is the first choice for the preparation of the fabric with electromagnetic function. So it is very important to study the dielectric constant of the metal fiber yarn for understanding the electromagnetic properties of the fabric.The dielectric constant of the metal is very complex, when the metal is in the form of fiber mixed with common fiber, it also exhibits complex characteristics. And the yarn structure is complex and changeable, so the dielectric constant of the metal fiber yarn is difficult to obtain. Therefore, in order to explore the dielectric constant and its measuring method of the metal fiber yarn, In this paper, polyester (PET) board and copper plate were used to simulate the structure of the common yarn and the structure of the metal fiber yarn in different ways. In addition, the metal fiber yarn and epoxy resin were mixed, and the equivalent series and parallel relationship was formed. At last, the dielectric constant in different series and parallel conditions is measured, the influence factor and the calculation formula of the dielectric constant are studied. The consistency of the test value and the calculated value is calculated, in oraer to explore the dielectric properties of metallic fiber yarns.(1) When the PET plate and air form the equivalent series connection and the equivalent parallel relationship, the error of the test value and the calculated value of the dielectric constant is small. With the increase of the percentage of PET in the sample, the dielectric constant increases. And the dielectric constant decreases with increasing frequency.(2) When the connection between the PET board and the copper plate is in series, the error of the dielectric constant is very small. The equivalent permittivity and the proportion of the two kinds of media have a nonlinear relationship. With the increase of the proportion of the air in the sample, the error increases gradually. When mixed with three kinds of media, the influence of the complex degree and the effect of the dielectric constant is totally different from that of the two media.When the PET plate, copper plate and air form parallel relationship, the error of the dielectric constant is small. The dielectric constant and the content of PET are linear correlation. When the metal is added between the parallel plates, the complexity of the dielectric constant is much higher than that only have PET plate.When the PET plate, copper plate and air are mixed, the model is close to the structure of the metal fiber yarn.(3) When the cotton/stainless steel yarn and resin are equivalent to the parallel relationship, the dielectric constant increases with the increase of the percentage of the yarn and the content of the stainless steel fiber in the yarn. Through calculation, the dielectric constant of the yarn is obtained.When the cotton/stainless steel yarn and resin are equivalent to several series and parallel relationship, the dielectric constant increases with the increase of the percentage of the yarn volume and the content of the stainless steel fiber in the yarn. Because of the complexity of the model, the dielectric constant of the yarn is not calculated, further research is needed.