Scientists Create World's Smallest FM Radio Transmitter with Graphene

Want to listen to the radio? What about listening to the smallest FM radio in the world? Scientists have taken advantage of graphene's special properties to create a nano-mechanical system that can creat FM signals. In essence, they've constructed the smallest FM radio transmitter ever created.

Graphene is a single atomic layer of carbon and is currently the strongest material known to man. With electrical properties that are superior to silicon, graphene is an ideal material for nanoelectromechanical systems (NEMS). NEMS systems are essentially scaled-down versions of microelectromechanical systems (MEMS), which are widely used for sensing vibration and acceleration. For example, MEMS sensors figure out which way your tablet is tilted so that the screen can be rotated.

"This work is significant in that it demonstrates an application of graphene that cannot be achieved using conventional materials," said James Hone, one of the researchers, in a news release. "And it's an important first step in advancing wireless signaling processing and designing ultrathin, efficient cell phones. Our devices are much smaller than any other sources of radio signals, and can be put on the same chip that's used for data processing."

In order to create this tiny radio, the researchers took advantage of graphene's mechanical stretchability in order to tune the output frequency of their custom oscillator. This allowed them to create a nanomechanical version of an electronic component known as a voltage controlled oscillator (VCO). With this VCO, its relatively easy to generate a frequency-modulated (FM) signal.

"This device is by far the smallest system that can create such FM signals," said Hone in a news release.

So what do the findings mean for the future? NEMS have many applications in wireless signal processing. Due to the continuous shrinking of electrical circuits known as "Moore's Law," today's cell phones have more computing power than systems that used to occupy entire rooms. However, some devices are much harder to miniaturize. This means that graphene NEMS can step in and help these systems; they are very compact and easily integrated with other types of electronics.

"There is a long way to go toward actual applications in this area, but this work is an important first step," said Hone. "We are excited to have demonstrated successfully how this wonder material can be used to achieve a practical technological graphene NEMS with silicon integrated circuits, making the oscillator design even more compact."

The findings are published in the journal Nature Nanotechnology.