Flexible antennas for wearable applications: Recent advances and design challenges

Wearable electronics are recently gaining significant scientific interest for a wide range of applications, including healthcare, sports, child monitoring, and consumer electronics. Integration of wireless functionalities into the aforementioned wearable electronics is key to their unobtrusive and round-the-clock performance. Therefore, one of the main challenges associated with wearable electronics lies in the realization of body-worn antennas that are flexible, ubiquitous, robust, and low-cost, while still exhibiting Radio-Frequency (RF) performance similar to that of their rigid copper counterparts. With this in mind, this paper presents a state-of-the-art overview of flexible antenna technologies reported for wearable applications. Specifically, the paper explains the fabrication process and outlines the appealing features of two flexible antenna categories, namely thin-film and fabric-based antennas. The paper also explains the design challenges associated with each of these two flexible antenna technologies, as attributed to their associated constraints and restrictions.