World’s tiniest radio only gets AM

Researchers from the University of Illinois and Northrop Grumman have built an AM radio using tubes.

That doesn’t seem too impressive — your grandma’s Monkey Wards Airline console had tubes, after all, and got AM and FM — except that these are carbon nanotubes. Those are sub-microscopic structures of highly engineered carbon molecules.

The tiny radio was built in a research lab in Linthicum, Md., and the first station they heard was WBAL (1090) in Baltimore, according to the Christian Science Monitor:

Electronic components built from carbon nanotubes have superior electrical properties compared with their silicon counterparts. Circuit designers, for instance, could pack more powerful radio transmitters into smaller packages than silicon-based components allow.

Until now, however, researchers have built carbon-nanotube electronic devices one tube at a time. The Grumman-Illinois team has perfected an approach that for the first time builds almost perfect horizontal arrays of tubes with near-perfect shapes.

This precision and uniformity prompted them to design transistors made from nanotubes, then incorporate them into a six-transistor radio. All six transistors could fit on a grain of sand, although when packaging is added, they become visible to the naked eye. Indeed, the team found it could build all the broad circuit types — from the active antenna to the audio amplifier driving the speaker — found in modern radios using its nanotransistors.

The first thing the researchers heard — and we’re not making this up — was a traffic report. Their report is scheduled to appear this week in the Proceedings of the National Academies of Science.

No word yet on whether the team is going to incorporate a tiny record player, like grandma’s console had, but I’m holding out hope.