Navigation Links
World's smallest radio uses single nanotube to pick up good vibrations
Date:10/31/2007

Berkeley -- Physicists at the University of California, Berkeley, have built the smallest radio yet - a single carbon nanotube one ten-thousandth the diameter of a human hair that requires only a battery and earphones to tune in to your favorite station.

The scientists successfully received their first FM broadcast last year - Derek & The Dominos' "Layla" and the Beach Boys' "Good Vibrations" transmitted from across the room. In homage to last year's 100th anniversary of the first voice and music radio transmission, they also transmitted and successfully tuned in to the first music piece broadcast in 1906, "Largo" from George Frederic Handel's opera "Xerxes."

"We were just in ecstasy when this worked," said team leader Alex Zettl, UC Berkeley professor of physics. "It was fantastic."

The nanoradio, which is currently configured as a receiver but could also work as a transmitter, is 100 billion times smaller than the first commercial radios, and could be used in any number of applications - from cell phones to microscopic devices that sense the environment and relay information via radio signals, Zettl said. Because it is extremely energy efficient, it would integrate well with microelectronic circuits.

"The nanotube radio may lead to radical new applications, such as radio-controlled devices small enough to exist in a human's bloodstream," the authors wrote in a paper published online today by the journal Nano Letters. The paper will appear in the print edition of Nano Letters later this month.

Authors of the nanoradio paper are Zettl, graduate student Kenneth Jensen, and their colleagues in UC Berkeley's Center of Integrated Nanomechanical Systems (COINS) and in the Materials Sciences Division at Lawrence Berkeley National Laboratory (LBNL). COINS is a Nanoscale Science and Engineering Research Center supported by the National Science Foundation (NSF).

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. The nanotubes also exhibit unusual electronic properties because of their size, which, for the nanotubes used in the radio receiver, are about 10 nanometers in diameter and several hundred nanometers long. A nanometer is one billionth of a meter; a human hair is about 50,000-100,000 nanometers in diameter.

In the nanoradio, a single carbon nanotube works as an all-in-one antenna, tuner, amplifier and demodulator for both AM and FM. These are separate components in a standard radio. A demodulator removes the AM or FM carrier frequency, which is in the kiloHertz and megaHertz range, respectively, to retrieve the lower frequency broadcast information.

The nanoradio detects radio signals in a radically new way - it vibrates thousands to millions of times per second in tune with the radio wave. This makes it a true nanoelectromechanical device, dubbed NEMS, that integrates the mechanical and electrical properties of nanoscale materials.

In a normal radio, ambient radio waves from different transmitting stations generate small currents at different frequencies in the antenna, while a tuner selects one of these frequencies to amplify. In the nanoradio, the nanotube, as the antenna, detects radio waves mechanically by vibrating at radio frequencies. The nanotube is placed in a vacuum and hooked to a battery, which covers its tip with negatively charged electrons, and the electric field of the radio wave pushes and pulls the tip thousands to millions of times per second.

While large objects, like a stiff wire or a wooden ruler pinned at one end, vibrate at low frequencies - between tens and hundreds of times per second - the tiny nanotubes vibrate at high frequencies ranging from kiloHertz (thousands of times per second) to hundreds of megaHertz (100 million times per second). Thus, a single nanotube naturally selects only one frequency.

Although it might seem that the vibrating nanotube yields a "one station" radio, the tension on the nanotube also influences its natural vibration frequency, just as the tension on a guitar string fine tunes its pitch. As a result, the physicists can tune in a desired frequency or station by "pulling" on the free tip of the nanotube with a positively charged electrode. This electrode also turns the nanotube into an amplifier. The voltage is high enough to pull electrons off the tip of the nanotube and, because the nanotube is simultaneously vibrating, the electron current from the tip is an amplified version of the incoming radio signal. This is similar to the field-emission amplification of old vacuum tube amplifiers used in early radios and televisions, Zettl said. The amplified output of this simple nanotube device is enough to drive a very sensitive earphone.

Finally, the field-emission and vibration together also demodulate the signal.

"I hate to sound like I'm selling a Ginsu knife - But wait, there's more! It also slices and dices! - but this one nanotube does everything; it performs all radio functions simultaneously and extremely efficiently," Zettl said. "It's ridiculously simple - that's the beauty of it."

Zettl's team assembles the nanoradios very simply, too. From nanotubes copiously produced in a carbon arc, they glue several to a fixed electrode. In a vacuum, they bring the electrode within a few microns of a second electrode, close enough for electrons to jump to it from the closest nanotube and create an electrical circuit. To achieve the desired length of the active nanotube, the team first runs a large current through the nanotube to the second electrode, which makes carbon atoms jump off the tip of the nanotube, trimming it down to size for operation within a particular frequency band. Connect a battery and earphones, and voila!

Reception by the initial radios is scratchy, which Zettl attributes in part to insufficient vacuum. In future nanoradios, a better vacuum can be obtained by insuring a cleaner environment, or perhaps by encasing the single nanotube inside a second, larger non-conducting nanotube, thereby retaining the nanoscale.

Zettl won't only be tuning in to oldies stations with his nanoradio. Because the radio static is actually the sound of atoms jumping on and off the tip of the nanotube, he hopes to use the nanoradio to sense the identity of atoms or even measure their masses, which is done today by cumbersome large mass spectrometers.


'/>"/>

Contact: Robert Sanders
rsanders@berkeley.edu
510-643-6998
University of California - Berkeley
Source:Eurekalert

Related biology technology :

1. OpGen Creates Map of Worlds Most Lethal Fungus
2. The DIG System Nonradioactive Automated High-Throughput In Situ Hybridization: a Powerful Tool for Functional Genomics Research
3. The DIG System Nonradioactive and Highly Sensitive Detection of Nucleic Acids
4. A simple method to sequence from bacterial colonies using [a-33P] radiolabeled ddNTPs and Thermo Sequenase
5. Development of Radioligand Binding Assays for the Motilin Receptor Using ScreenReady Targets.
6. Georgia healthcare system to install GEs radio frequency ID
7. See how they run: Radio ads and Google
8. TomoTherapys 100th radiology system reaches public sector
9. Satellite radio can promote your national brand
10. Radiology advance points way to non-invasive brain-cancer treatment
11. Madison music featured on Internet radio station
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/23/2017)... ... June 23, 2017 , ... Ken Hanson, a medical ... Physik Instrumente USA, have been selected as this year’s recipients of two top awards ... have been invited along with other honorees to accept their awards at a banquet ...
(Date:6/22/2017)... ... 21, 2017 , ... RMC Pharmaceutical Solutions, Inc. announces the ... to manage the new site. , Tim has 25 years of pharmaceutical experience, ... role as the Director of Manufacturing and Supplier Quality Assessment. This group ...
(Date:6/22/2017)... ... 22, 2017 , ... For the months of May and ... Spotlight series on “Cell Therapy Regulation” for its regenerative medicine followship. ... unique regulatory challenges of stem cell medical research. , Stem cell clinical trials ...
(Date:6/22/2017)... ... 22, 2017 , ... Charm Sciences, Inc. is pleased to announce that its ... be appropriate as a screening test at dairies and farms for raw commingled cow ... the Charm EZ Lite system. These systems are a combination incubator and reader in ...
Breaking Biology Technology:
(Date:5/16/2017)... TEANECK, N.J. , May 16, 2017  Veratad ... leading provider of online age and identity verification solutions, ... the K(NO)W Identity Conference 2017, May 15 thru May ... Ronald Regan Building and International Trade Center. ... across the globe and in today,s quickly evolving digital ...
(Date:4/18/2017)... , April 18, 2017  Socionext Inc., a global expert in ... media edge server, the M820, which features the company,s hybrid codec ... provided by Tera Probe, Inc., will be showcased during the upcoming ... NAB show at the Las Vegas Convention ... Click ...
(Date:4/11/2017)... Apr. 11, 2017 Research and Markets has ... report to their offering. ... The global eye tracking market to grow at a CAGR of ... Eye Tracking Market 2017-2021, has been prepared based on an in-depth ... market landscape and its growth prospects over the coming years. The ...
Breaking Biology News(10 mins):