For years, scientists have struggled to find new ways to efficiently collect radio waves from the environment in order to power small devices. However, so far, the source of these signals has not been as widespread as the wireless network (Wi-Fi). Recently, a research team from the National University of Singapore (NUS) introduced a new chip that they have developed to power LEDs and other small electronic devices/sensors.
Research leader Prof. Yang Hyunsoo (left) and first author Dr. Raghav Sharma
Harvesting radio energy in the environment and then converting it to output meaningful power has been a daunting challenge for many years.
The good news is that scientists from the National University of Singapore and Tohoku University in Japan have developed what they call a "self-torque oscillator" (STO).
A relatively new class of tiny devices, they have the ability to generate microwaves, but until now the output power has been fairly low. Based on this, the research team came up with a new solution to integrate multiple STOs on one chip to increase the output power.
To achieve this, however, the research team has been working hard to design and test optimal layouts to address issues such as spacing and low-frequency response. The final delivery demonstration plan includes eight STOs connected in series.
The array absorbs the 2.4GHz radio waves generated by Wi-Fi signals and converts them into DC voltage signals. After passing to the capacitor, it can be used for 1.6V LED.
After charging the capacitor for 5 seconds, the LED will remain lit for one minute even if the external power supply is cut off.
"We live in a world surrounded by Wi-Fi signals, but when we're not using them to access the internet, they're inactive, wasting energy," said study author Professor Yang Hyunsoo.
The new research is the first step in a shift in which readily available 2.4GHz radio waves will become a source of green energy to reduce the battery requirements of the electronic devices we use regularly.
In this way, some IoT devices can be powered using radio signals. With the popularity of smart home and smart city applications, this research work may be efficiently applied in systems such as communication, computing, and neuromorphism.
The research team is now working to increase the number of STOs in the array to improve energy harvesting, and is exploring how it could be used to power other electronic devices and sensors.
Details of the research have been published in the recent issue of the journal Nature Communications.
The original title is "Electrically connected spin-torque oscillators array for 2.4?GHz WiFi band transmission and energy harvesting".
