Knitted textile antenna structures: Survey, characterization, simplified modeling approach, and applications

Knitted textile antennas hold significant promise for wearable communication and sensing; however, designing and evaluating them requires simulation workflows that balance accuracy with computational efficiency. This study reviews knitted antennas and introduces a novel approach based on hybrid yarns with embedded microwires. Most textile antennas reported to date are fabricated using metallized polyamide fibers; however, this study focuses on the design, simulation, and realization of antennas based on so-called hybrid yarns containing embedded microwires, which exhibit significantly lower electrical resistance - by several orders of magnitude - compared to metallized polyamide yarns. Waveguide measurements reveal anisotropic permittivity and highlight the influence of material composition and knit geometry. These data are implemented in CST Studio Suite through an Effective Material Approach (EMA) that enables the emulation of real-world antenna behavior without modeling every individual yarn. A bowtie antenna serves as a representative design, simulated using the EMA and compared against both a solid silver simulation model and experimental measurements. Despite minor quantitative deviations, the results validate the approach and lay the groundwork for future design guidelines for knitted textile antennas. To illustrate the application potential, two demonstrators are presented: a knitted bowtie frequency resonator for wearable strain monitoring, and a wireless data-transmission link using knitted antennas with a textile LED readout.