High-Strength, Metalized Fibers for Conformal Load Bearing Antenna Applications

Abstract

We propose the use of high strength, metal-coated Kevlar yarns to weave flexible, conformal, and load-bearing antennas for an emerging class of applications emphasizing multiple functionality. In particular, here we present a unified, quantitative analysis of multiple properties of conductors as load-bearing materials in stress-, weight-, and shape-critical applications (e.g., in aerial vehicles), suggesting advantageous electrical conductor configurations to be metal-coated, multi-filament, high strength fibers. We then describe the fabrication of highly conductive metal coated Kevlar yarns, their mechanical and electrical properties, and the weaving of a flexible, stretchable, volumetric spiral antenna. The high frequency response of the antenna is found to match that of a traditionally made antenna comprised of electroplated copper on a rigid ceramic (Rogers TMM4) substrate. At low frequencies, the relatively lower conductivity of the metal-coated kevlar yarn leads to higher resistive losses compared to the traditional electroplated copper. We discuss strategies for mitigating such losses, and other means of improvement. More broadly, the results described here suggest a novel direction for multi-functional antenna design and applications, enabled by the superior mechanical characteristics of the composite conducting fibers, and the flexible, conformable, woven antenna architectures they help achieve.