Textile SIW antennas as hybrid energy harvesting and power management platforms

A compact, highly-integrated and unobtrusive wearable textile antenna system, able to establish a reliable and energy-efficient wireless body-centric communication link in the [2.4-2.4835]-GHz Industrial, Scientific and Medical band and enabling energy harvesting from three different energy sources, is presented. Our design approach relies on further extending the functionality of a carefully selected textile antenna by exploiting its surface as an energy scavenging and power management platform. More specific, two different ultra-flexible solar cells, a micro-energy cell and a flexible power management system are integrated onto a wearable substrate integrated waveguide cavity-backed textile slot antenna to enable energy harvesting from both solar and artificial light. Furthermore, thermal body energy harvesting, via an externally connected thermoelectric generator, is enabled by including an ultra-low voltage step-up converter. Measurements in four well-chosen indoor scenarios demonstrate that a hybrid energy-harvesting approach is necessary to obtain a more continuous flow and a higher amount of scavenged energy, leading to a higher system autonomy and/or reduced battery size.