Mobile phones to be powered by micro-jet engines

Engineers at the Georgia Institute of Technology in the US have made advances in batch producing miniaturised, jet engine-based generators from a single stack of bonded silicon wafers - potentially unlocking a new power source for mobile phones and other portable electronic devices.

New Scientist magazine has reported that by spinning a tiny magnet above a mesh of interleaved coils etched into a wafer, engineers David Arnold and Mark Allen have built the first silicon-compatible device capable of converting mechanical energy (produced by a rotating micro-turbine) into usable amounts of electrical energy.

The benefits of microengines, according to the October New Scientist report, is that they pack in at least 10 times more energy per volume of fuel than conventional lithium batteries. They also take up less space and work more smoothly than other options like fuel cells.

"Jet engines are remarkable pieces of equipment in terms of efficiency," explains Stuart Jacobson at the Massachusetts Institute of Technology, US, who collaborates with Arnold and Allen.

Obtaining usable amounts of energy from a micro-scale device is crucial if micro-engines are to find their way into everyday electronic products.

The US Army is keen to examine micro-jet engine generators and expects that soldiers - who currently rely on battery-powered laptops, night-vision goggles and GPS systems - will be among the first to use the microengines. "The army has a tremendous power problem - soldiers get bogged down by their batteries," explains Jacobson.

Arnold and Allen will present their advance at the International Conference on Micro Electro Mechanical Systems (MEMS) in January 2005.

For more information: http://www.cmmt.gatech.edu/