Chinese radio wave-powered chip may make 'always-on smartphone' a reality
Invention of a chip powered by radio waves may lead to battery-free devices
Chinese scientists have developed a credit card-sized chip that could be powered by radio waves around us, according to a new study at the Chinese Academy of Sciences.
Improvement of the technology could eventually lead to battery-free electronic devices such as a smartphone that could stay on forever.
The chip harnessed energy from ambient radio waves with frequency similar to the 2G mobile network, said Professor Feng Peng, a researcher involved in the project with the academy's Institute of Semiconductors.
What it could do at the moment was still fairly primitive, Feng said. For instance, the chip could be integrated with a temperature sensor and beam a warning message to security personnel when it detected a fire.
But the biggest advantage of the technology was that it enabled electric circuits to operate constantly without having to be connected to a power source, the researcher said.
"A battery needs to be replaced or recharged regularly, and it's not everywhere that you can use an AC outlet," Feng said.
"If we can say goodbye to batteries and wires, we can leap comfortably into the Internet of Things."
Scientists have long dreamed of using the increasing amount of radio waves as "bread from the sky" for small electronics.
Laboratories around the world have come up with various prototypes from television sets to microwave ovens to try to tap into the radio waves, but none of the devices are yet ready for commercial use.
The biggest challenge was the low energy carried by these free radio waves.
The new Chinese chip, although it performed better than most of its competitors, still relied on a dedicated power source to generate strong enough radio waves for operation, according to the paper published on the latest issue of IEEE Sensors Journal.
But Feng said battery-free smartphones could be possible with advances in the technology. There was still plenty of room to increase the energy gathering efficiency while reducing the energy consumption of the internal circuits, he said.
"If coupled with other energy harnessing methods such as thin film solar cells, the first mobile phone that never goes power off may come out faster than we thought," Feng said.
The Chinese chip now cost 10 yuan (HK$12.70) to make, and mass production could further cut the price, the team said.
It could be applied in many sectors in need of wireless sensors, such as warehouses, hospitals, schools and military facilities.