One of the biggest challenges for small wearable devices is how to power them. The smaller the devices, the less space there is for the batteries, which makes runtime a problem in some cases. A group of researchers led by Huanyu “Larry” Cheng of Penn State University has developed a new method of feeding wearable devices using energy captured from radio waves.
Current sources of energy for wearable health monitoring devices have disadvantages. Solar energy can only collect energy when exposed to the sun, while triboelectric devices can only collect energy when the body is in motion. Cheng says the researchers are not trying to replace these energy methods, but are trying to provide additional consistent power for wearable devices. The team developed an extensible broadband dipole antenna system that can wirelessly transmit data collected from health monitoring sensors.
The device consists of a pair of extensible metal antennas integrated into the conductive graphene with a metal coating. The system’s broadband design allows it to retain frequency functions even when stretched, folded and twisted. This system is connected to an extensible rectifier circuit to create a rectified antenna that can convert the energy of electromagnetic waves into electricity.
Electricity can then be used to power wireless devices or charge energy storage devices like batteries and supercapacitors. The researchers believe the technology is a building block and can be combined with wireless transmissible data devices to provide a critical component for working with existing sensor modules developed by the team. The researchers’ next step will be to explore miniaturized versions of the circuits and work on developing the rectifier’s elasticity.
The team believes it has created a platform that could be easily combined and applied with other modules developed in the past. The researchers will explore opportunities to extend or adapt the new technology to other applications.