New technique converts ambient radiofrequency signals into DC voltage

Wireless technologies like Wi-Fi, Bluetooth, and 5G rely on radio frequency (RF) signals to send and receive data. A new prototype of an energy harvesting module – developed by a team led by scientists from the National University of Singapore (NUS) – can now convert ambient or ‘waste’ RF signals into DC voltage that can be used to power small electronic devices.

According to NUS, RF energy harvesting technologies can reduce battery dependency, extend device lifetimes, minimise environmental impact, and enhance the feasibility of wireless sensor networks and IoT devices in remote areas.

However, RF energy harvesting technologies face challenges due to low ambient RF signal power (typically less than -20dBm), where current rectifier technology either fails to operate or exhibits a low RF-to-DC conversion efficiency. Improving antenna efficiency and impedance matching can enhance performance, but this increases on-chip size.

To address these challenges, a team of NUS researchers, working in collaboration with scientists from Tohoku University (TU) in Japan and University of Messina (UNIME) in Italy, has developed a compact and sensitive rectifier technology that uses nanoscale spin-rectifier (SR) to convert ambient wireless radio frequency signals at power less than -20dBm to a DC voltage.