Engineers at Aalto University have made a breakthrough in wireless charging of devices over long distances.
The team optimised the interaction between antennas transmitting and receiving power, using "radiation suppression" to advance the technology.
While wireless charging over short distances through induction pads is widespread, efficiency takes a significant hit when attempting to charge devices at longer distances. However, the researchers at Aalto University have now demonstrated that high efficiency can be sustained over extended distances by suppressing the radiation resistance of loop antennas used in power transmission.
Previously renowned for creating an omnidirectional wireless charging system capable of charging devices regardless of their orientation, the researchers have now expanded their work to explore a dynamic theory of wireless charging. This new approach delves deeply into both near (non-radiative) and far (radiative) distances and conditions. Their findings reveal that an astonishing transfer efficiency of more than 80% can be achieved at distances approximately five times the size of the antenna, using the optimal frequency within the hundred-megahertz range.
Lead author Nam Ha-Van, a postdoctoral researcher at Aalto University, said: "We wanted to balance effectively transferring power with the radiation loss that always happens over longer distances. It turns out that when the currents in the loop antennas have equal amplitudes and opposite phases, we can cancel the radiation loss, thus boosting efficiency."
Ha-Van emphasised the broader implications of their work: "This is all about figuring out the optimal setup for wireless power transfer, whether near or far. With our approach, we can now extend the transfer distance beyond that of conventional wireless charging systems, while maintaining high efficiency."
Source: Aalto University