Stanford University engineers have developed a new way to charge devices wirelessly, while they are in motion.

Existing wireless charging systems (including ones that charge electric cars) typically only work when stationary.

The researchers found that their new system could transfer the same amount of power when moved around up to one metre away — monitored by the brightness of the bulb remaining constant.

Shanhui Fan and colleagues created a wireless power transfer system that can achieve high-efficiency power transfer over varying distances using the principle of parity-time symmetry — a concept from quantum mechanics.

The authors were able to produce electrical circuitry that could receive power constantly over a distance variation of approximately one metre.

They were able to power an LED, producing a constant brightness, as it was moved away from the power source.

The authors say their findings could have applications in delivering power to moving devices or vehicles, where the transfer distance and orientation can change continuously.

The study is accessible here.