TECH SPECIAL.... Flexible device turns WiFi signals into electricity

Flexible device turns WiFi signals into electricity

A new device made from inexpensive materials could power electronics, wearables as well as medical devices

MIT scientists have developed the first fully flexible device that can convert energy from WiFi signals into electricity, paving the way for wirelessly powering electronics without batteries. Devices that convert AC electromagnetic waves into DC electricity are known as ‘rectennas’.

The researchers demonstrate a new kind of rectenna that uses a flexible radio-frequency (RF) antenna which captures electromagnetic waves — including those carrying WiFi — as AC waveforms.

Early application

“We have come up with a new way to power the electronics systems of the future — by harvesting WiFi energy in a way that’s easily integrated in large areas — to bring intelligence to every object around us,” says Tomas Palacios, a professor at Massachusetts Institute of Technology (MIT) in the US.

Promising early applications for the proposed rectenna include powering flexible and wearable electronics, medical devices and sensors for the ‘internet of things’.

Flexible smartphones, for instance, are a new market for major tech firms. In experiments, the researchers’ device can produce about 40 microwatts of power when exposed to the typical power levels of WiFi signals (around 150 microwatts). That is enough power to light up a simple mobile display or silicon chips.

Output efficiency

Another possible application is powering the data communications of implantable medical devices. For example, researchers are developing pills that can be swallowed by patients and stream health data back to a computer for diagnostics.

The output efficiency for the current device stands at 40 per cent, depending on the input power of the WiFi input. The team is now working on improving the efficiency.

— PTI