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A record-breaking RF energy harvester designed by researchers from Holst Centre and the Eindhoven University of Technology (TU/e) has been shortlisted for a prestigious Institution of Engineering and Technology (IET) Innovation Award. The device, which has been nominated in the "Built Environment" category, sets new standards for size and energy conversion. By eliminating the need for batteries or power cables, the harvester could help kick start the Internet of Things (IoT) and smart buildings markets.
Smart buildings of the future will be equipped with hundreds, even thousands, of wireless sensors. These sensors will, for example, enable automatic control of light and heating to reduce the building's overall energy consumption. However, they can't be powered by cables or conventional batteries due to the inconvenience and cost to consumers as well as environmental issues.
Hence the Holst Centre-TU/e team has developed a "wireless battery" that harvests energy from a central wireless power transmitter operating in the 868 MHz (Europe) or 915 MHz (North America) license-free ISM frequency band. Such wireless batteries could power sensor nodes throughout a smart building from one or two transmitters, aiding the uptake of smart building systems.
Development of the wireless battery is led by Huib Visser, whose team includes Holst Centre colleague Hans Pflug and Shady Keyrouz from the TU/e. "We are thrilled to be shortlisted for the prestigious IET innovation award," said Huib. "Being a finalist will raise awareness of our invention's capabilities as well as the immense possibilities smart building applications and the IoT bring for companies and consumers."
The Holst Centre-TU/e wireless battery comprises a miniaturized antenna, rectifier, power management circuit and an energy storage device. Careful co-design of all the subsystems has resulted in the world's smallest and most efficient rectifying antenna for RF-to-DC power conversion. Consequently, the device can deliver a 60 mW pulse of DC power lasting 40 ms every 2 minutes at distances up to 12 meters from the transmitter. This is more than enough to wake up a radio, perform a sensing operation, transmit the data and switch off again.
Currently in the prototype phase, the wireless battery is already gathering market interest. "Compared to other solutions, Holst Centre's RF harvester is the most powerful in terms of its size / power efficiency ratio. It would enable simpler system architectures plus greater system lifetimes and autonomy. It represents a real innovation as an alternative energy source, delivering enough predictable and consistent power to ensure a real potential use for standalone IoT devices," said Cyril Voillequin, Thales Communications and Security.
The winners of the IET Innovation Awards will be announced at a ceremony on November 18 at The Brewery, London, UK.