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A nanoradio is a radio receiver or transmitter constructed on a nanometer scale. Currently only receivers have been developed and they are structured around a carbon nanotube. The first such device was described in October 2007 by a team led by physicist Alex Zettl.[1]
The nanotube, about 10 nanometers in diameter and several hundred nanometers long, is contained in a vacuum and one of its ends is connected to an electrode of a battery. The other electrode is placed a short distance from the nanotube's other end. The tube, now charged, will vibrate in tune with any external electromagnetic signal, effectively acting as an antenna. The favorable vibration frequency can be adjusted by changing the applied voltage, which allows to tune the radio to different carrier frequencies. The field electron emission effect causes a current to flow, as electrons tunnel across the gap between the tube and the second electrode. This current represents an amplified version of the radio signal; no demodulation is necessary.[2][3]