Characterization of the Electromagnetic Properties of Materials for Wearable Antennas

Abstract

This paper presents the results of measurements of the complex permittivity of non-textile and textile materials, which can be used for an efficient design of wearable antennas. Measurements of the electromagnetic properties of the materials were done at a single frequency of 2.56 GHz using the cavity perturbation method. The results show that non-textile materials (leather, paper, plastic from 3D DLP printing) have a real part of the complex permittivity (${\varepsilon_{\mathrm{r}}}^{\prime}$) in the range of 2.0-3.0, while ${\varepsilon_{\mathrm{r}}}^{\prime}$ of textile materials is in the range of 1.0-2.0. The results also showed that fabric structure (woven, knitted, or non-woven) has a direct effect on the ${\varepsilon_{\mathrm{r}}}^{\prime}$, while the type of fibers (natural or synthetic) has a direct effect on the imaginary part of the permittivity and loss tangent.