ARLA/CLUSTER: O mais pequeno transmissor de FM do Mundo é feito à base de grafeno

[João Costa > CT1FBF]

World's tiniest FM transmitter made from Graphene

Graphene has many talents. And now it can count radio transmission among them.

A team led by James Hone and Kenneth Shepard at Columbia University in
New York has demonstrated a device built from a strip of graphene that
can transmit FM radio signals. The device, the team says, is the
smallest FM transmitter yet made.

Many research groups have built graphene transistors that could be
used in future RF circuits such as signal processors. Hone and his
colleagues decided to test a different radio application for graphene,
by building a moving, vibrating, electromechanical device. The team
reckons that such graphene-based nanoelectromechanical systems (NEMS)
could be more compact and easier to integrate onto chips than silicon
MEMS and quartz devices, which are used today to pick up and filter RF
signals in smartphones and other gadgets.

To build a graphene transmitter, the team suspended a 2-4
micrometer-long strip of graphene above a metal electrode. By applying
a voltage to the electrode, they could draw the strip of graphene
down. The resulting strain altered the strip's resonant frequency,
tuning it up much as you might tighten a guitar string. By altering
the voltage on the gate, the team found they could use the graphene
device to generate a frequency-modulated electromagnetic signal. In a
paper published this week in Nature Nanotechnology, they report the
device could transmit radio signals at 100 MHz, right in the center of
the FM band.

http://spectrum.ieee.org/tech-talk/semiconductors/devices/worlds-tiniest-fm-transmitter-made-from-graphene

Our thanks to Stephen G7VFY for spotting this item