Harnessing Energy for Portable Electronics through Wi-Fi Signals

MIT researchers designed a blueprint for a device that could harvest terahertz radiation to enable self-powering portable electronics.
Fabienne Lang

Your Wi-Fi router emits terahertz waves, or electromagnetic waves, that have a frequency between what a microwave and an infrared light emit.

These waves, also known as T-rays, are almost everywhere in our day to day lives, and if harnessed correctly can serve as an energy source. This is what MIT researchers have been working on, and, in fact, have designed a blueprint for a device that could capture and convert these ambient terahertz waves into energy to charge up electronic devices. 

Their findings were published in Science Advances


Alternate energy source

With terahertz waves so pervasive in our daily lives, it would be an incredible feat to passively harness them and make use of them. Imagine, for example, having a little device that easily pops onto your smartphone that soaks up these T-rays and uses their energy to charge up your phone. 

Up until now, terahertz waves have been wasted as there has been no practical method for capturing and converting them into usable energy. 

This is why it's so exciting to hear that physicists from MIT believe they have created a blueprint for such a device to turn terahertz into a form of electricity. 

Harnessing Energy for Portable Electronics through Wi-Fi Signals
Schematic figure from the researchers' paper, Source: MIT

Their design makes use of the atomic behavior of graphene, a carbon material, that when combined with boron nitride, the electrons of the graphene change their motion towards a common direction. As such, any incoming terahertz waves would reshuffle to all go towards the same direction, as a direct current. 

"This would work very much like a solar cell, except for a different frequency range, to passively collect and convert ambient energy," explained co-author of the study, Liang Fu, the Lawrence C. and Sarah W. Biedenharn Career Development Associate Professor of Physics at MIT.

Most Popular

Lead author of the study, Hiroki Isobe, a postdoc in MIT's Materials Research Laboratory said "We are surrounded by electromagnetic waves in the terahertz range. If we can convert that energy into an energy source we can use for daily life, that would help to address the energy challenges we are facing right now."

The researchers have filed a patent for their design and are working closely with experimental physicists at MIT to create an actual device based on their design.

Isobe and the team's hope is that such a device could ultimately be used to power implants in a patient's body, for instance. This way surgery would not be required in order to change an implant's batteries. 

Fu said "We are taking a quantum material with some asymmetry at the atomic scale, that can now  be utilized, which opens up a lot of possibilities."