Japan to enable wireless charging through the air

Wouldn’t it be convenient to be able to charge smartphones and other devices simply by holding them in your hand? Japan is now planning a corresponding technological advance that should make exactly that possible. This should make cordless power transmission feasible indoors and outdoors.

Cordless power transmission in Japan

Stanford University’s Japan-based startup Aeterlink launched a new technology in November 2021 that can transmit electricity via microwaves at a range of up to 20 meters.

As part of a presentation of the wireless charging technology, a construction company’s offices were outfitted with transmitters and the special receivers. The transmitters were mounted on the ceiling and were capable of supplying electricity to smart office chairs using the 920 MHz band.

The chairs can then automatically report to the building management system whether they are occupied, allowing more precise control of the air conditioning system.

https://www.youtube.com/watch?v=p4BrkYHMJQI

By releasing frequencies for wireless power transmission, the Japanese government is looking to tap into a whole new market. However, due to interference with the transmission signals, the new technology is currently only of limited market suitability, but this is expected to change soon.

Wireless power supply to be available outdoors from 2024

Authorities will initially enable wireless power transmission indoors. From 2024, the technology will then even be allowed outdoors. Initially, three frequency bands will be released: 920-MHz for environments with humans, and the 2.4- and 5.7-GHz networks for unmanned environments.

Charging power is currently extremely limited due to the 920-MHz band being harmless to humans. Only a few milliwatts are currently offered. However, according to Aeterlink, this is sufficient for certain sensors on devices and machines that could otherwise hardly be supplied with power.

Sensors in robotic hands in production facilities that are difficult to charge via cable are cited as an example. Commercialization of cordless power to factories is expected to begin next year.

Aeterlink founder Yuji Tanabe had co-developed cordless charging for medical implants such as pacemakers at Stanford University in the U.S., among other things, and is considered a pioneer in this field.

Wireless charging thanks to 5G

In Japan, mobile network provider Softbank is also looking into this technology. Together with Kyoto University, the Kanazawa Institute of Technology and the National Institute of Information and Communications Technology, they are working on a technology that will then be housed in transmitters for 5G mobile networks.

The charging power should be able to be sufficient to wirelessly power smartwatches or in-ear headphones. The electrical charge is realized in the 28-gigahertz high-frequency band and should initially be able to transmit at least one milliwatt over a range of ten meters. However, Softbank wants to increase the range to 100 meters and hopes to introduce the technology as early as 2025.