The wireless charging device that will power up your mobile from across the room



It could spell the end to tangled charger leads and your favourite gadget running out of power just when you need it most.

Japanese firm Fujitsu has unveiled technology that uses magnets to recharge more than one gadget at once – entirely without wires.

The system means that devices can be charged up at a distance of a several metres and could lead to wireless charging ‘hotspots’ in public places by 2012.

Fujitsu demonstrates two lightbulbs lighting up using its wireless charging technology

Two mobile phones are charged wirelessly during Fujitsu's demonstration

In theory, the system should be entirely safe for humans in the charging field because power is only transmitted between coils that resonate at the same frequency.

But it is likely that many people will have concerns about the technology in a similar way to people’s fears over Wi-Fi and mobile phone masts.

A cross-section of the two coils in resonance

The technology uses magnetic resonance to send electrical charge over through the air between the charger and the device. A coil of wire and a capacitor create the resonance between it and the power receiver.

The system could lead to a wide range of future applications including charging zones for electric cars and power transmission for computer chips, according to Fujitsu.

Fujitsu claims that the technology will lead to charging systems that can recharge a device in 1/150th the time currently required.

A huge upsurge in the number of power-hungry devices like iPhones and iPads in recent years has seen an increased need for a breakthrough such as wireless charging.



Fujitsu said in a statement: ‘This technology paves the way to integrating compact wireless charging functions into mobile phones and enabling multiple portable devices to be charged simultaneously without any restrictions on their position with respect to the charger.’

Fujitsu's design uses magnetic resonance rather than the more typical electromagnetic induction method

Many current wireless charging systems rely on electromagnetic induction between two coils - a method that works over a very short distance and means that gadgets are placed on a charging pad. These systems often waste a lot of the power consumed.

Fujitsu's system is based on magnetic resonance in which power can be wirelessly sent between two coils that are tuned to resonate at the same frequency.

Tests showed it working across a gap of about 15 centimetres although the firm claims that it will eventually be capable of transferring power across several metres.



The further away it is from the device, the more power is lost in the transfer, however.

The system is similar to technology devised by US firm Witricity which also uses magnetic resonance to transfer electricity to devices over several metres.

Details of the technology were presented at an engineering conference in Osaka, Japan.