Broadband wearable textile antenna with embroidered vias for on-body communications

Abstract

Low profile and flexible antenna types including microstrip patch antenna and planar inverted-F antenna have been popularly utilized for wearable antenna designs in many kinds of literature. However, due to their inherent disadvantage (narrow bandwidth), frequency shift caused by human body movements becomes a challenging problem. In this study, a broadband microstrip monopolar patch antenna proposed in previous work is adopted and modified for body area network use. The modified structure is made of all textile materials instead of Printed Circuit Board (PCB), which allows it to be directly integrated with clothes. The set of conductive vias using copper wires to short the original circular patch antenna is replaced by embroidered vias using conductive threads. Such antenna maintains a simple structure, radiates omni-directionally at 2.4 GHz - 2.5 GHz Industrial, Scientific and Medical band and realize a wide bandwidth up to 18%, which is favoured for on-body communication applications. Simulations have shown a satisfactory level of immunity against detuning while the antenna is in bending, crumpling and on body situations. A prototype was fabricated with embroidered vias sewed by hand, and the measured antenna performance will be presented and discussed.