06 January 2009

Wireless Power The Next Big Thing?
Breakthrough in wireless power pulls plug on cables

An artist's depiction of a solar satellite, which could send energy wirelessly to a space vessel or planetary surface

Small, battery-powered gadgets make powerful computing portable. Unfortunately, there's still a continual need to recharge the batteries of phones, laptops, cameras, and MP3 players by hooking them up to a tangle of wires. The latest technology trends proposed a way to cut the cords by wirelessly supplying power to devices.

The idea of beaming power through the air has been around for nearly two centuries, and it is used to some extent today to power some types of radio-frequency identification (RFID) tags.

The phenomenon behind this sort of wireless-energy transfer is called inductive coupling, and it occurs when an electric current passes through wires in, for instance, an RFID reader.

No more batteries, no more chargers and no more wire spaghetti. This is the future promised by "wireless power", a means of broadcasting electricity through the air to laptops, iPods and other gadgets without the need for cables and sockets.

Untethered lighting, audio speakers and digital picture frames are expected to be among the first commercial products demonstrated in Las Vegas this week at the International Consumer Electronics Show, the world's biggest gadgets tradeshow.

"If each room had wireless power, you'd know that once you walked through the front door your mobile would start charging up - even while still in your bag or pocket. You'd never need to hunt for the right charger again."

Among the companies showcasing the ambitious technology at CES is PowerBeam. Its system turns electricity into an invisible laser, then literally beams it, as heat, across the room to a solar cell that converts it back into electricity.

David Graham, the co-founder of PowerBeam, told the Observer: "We're going to delete the word 'recharge' from the English dictionary. If your cellphone is recharging on your desk all day, you won't be thinking about it."

The new wireless power technology is suppoused to be displayed at CES and experts believe this is just the beginning and that eventually wireless electricity - dubbed "WiTricity" by some - could do for battery life what WiFi did for the internet

Wireless energy transfer or wireless power transmission is the process that takes place in any system where electrical energy is transmitted from a power source to an electrical load, without interconnecting wires in an electrical grid. Wireless transmission is ideal in cases where instantaneous or continuous energy transfer is needed, but interconnecting wires are inconvenient, hazardous, or impossible.

Unlike the far field wireless power transmission systems based on traveling EM waves, WiTricity employs near field inductive coupling through magnetic fields, which interact far more weakly with surrounding objects, including biological tissue.

In particular, it is based on using 'strongly-coupled' resonances to achieve a high power-transmission efficiency.

Aristeidis Karalis, referring to the team's experimental demonstration, says that "the usual non-resonant magnetic induction would be almost 1 million times less efficient in this particular system". The researchers suggest that the exposure levels will be below the threshold for FCC safety regulations, and the radiated-power levels will also comply with the FCC radio interference regulations.

It is not known exactly why this technology had not been developed. Researchers attribute it to various reasons ranging from the limitations of well-known physical laws, to simply a lack of need. Only recently have modern consumers obtained a high number of portable electronic devices which currently require batteries and plug-in chargers