An international research team created a new way to harvest energy from radio waves and use it to power wearable devices.
Current energy sources for wearable health monitoring devices have their place in powering sensing devices, but there are setbacks. With solar energy, power is only harvested when the device is exposed to the sun. Self-powered triboelectric power only harvests energy when the body is in motion. The team’s goal was not to replace these power methods, but rather supplement for when those power options are not available.
The stretchable wideband dipole antenna system can wirelessly transmit data collected from health monitoring sensors. The system consists of two stretchable metal antennas integrated onto conductive graphene material with a metal coating. A wideband design allows it to retain frequency functions when stretched, bent or twisted. It is connected to a stretchable rectifying circuit which creates a rectified antenna that can convert energy from electromagnetic waves into energy. This electricity can be used to power wireless devices or to charge energy storage devices, like batteries or supercapacitors.
The rectenna can convert radio waves from an ambient environment into energy to power sensing modules on the device. It tracks temperature, hydration and pulse oxygen levels. Compared to other energy sources, this method produces less energy but it generates power continuously.
The researchers from Wuhan University of Technology (China), Heriot-Watt University (Scotland), Zhejiang University of Technology (China), Hebei University of Technology (China) and Pennsylvania State University next plan to explore mini versions of circuits and further develop stretchability of the rectifier.
A paper on this technology was published in Materials Today Physics.