Berkeley researchers use nanotube to build world's tiniest radio

Computerworld - Physicists at the University of California, Berkeley, have built the world's smallest radio out of single carbon nanotube one ten-thousandth the width of a human hair.

Researchers say the tiny radio needs only a battery and a pair of earphones to hook listeners up with their favorite radio stations. But that's not all the new device could be good for.

The radio's tiny size could make cell phones more efficient, or it even could be used in radio-controlled devices that flow through the human blood stream, according to a paper written in part by team leader Alex Zettl, a U.C. Berkeley professor of physics. Zettl also noted that he hopes to use the radio to replace cumbersome devices used today to identify atoms or even measure their mass, since the new radio can pick up on atoms jumping on and off the tip of the nanotube.

"We were just in ecstasy when this worked," said Zettl, in a written statement. "It was fantastic."

The device, which researchers are calling the nanoradio, is currently set up to act only as a receiver but could also work as a transmitter. U.C. Berkeley reported that the nanoradio is 100 billion times smaller than the first commercial radios.

Nanotubes are rolled-up sheets of interlocked carbon atoms that form a tube so strong that some scientists have suggested using a nanotube wire to tether satellites in a fixed position above Earth, according to Berkeley researchers.

In the nanoradio, one carbon nanotube serves as an antenna, a tuner, an amplifier and even a demodulator picking up both AM and FM frequencies -- an all-in-one radio. These are separate components in a standard radio.

A Berkeley release explained that the nanoradio uses a new method to detect radio signals: It vibrates thousands to millions of times per second in tune with the radio wave.

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