If engineers at Advanced Diamond Technologies Inc., Champaign, Ill., are on the right track, future communication devices could rely on ultra-nanocrystalline diamond (UNCD) for ever-higher operating frequencies. The company licensed much of UNCD technology from Argonne National Laboratory. It is based on 5-nm grain size synthetic diamond, 1 billionth the size of grains in normal diamonds.

The tight grains gives UNCD high strength and low surface friction, as well as the highest known acoustic velocity of any material. This translates into higher resonator frequencies. A 100-nm tuning fork made of UNCD, for example, can vibrate up to 100 billion times/sec. UNCD also doesn't lose any of its properties after exposure to the environment, a key point for consumer and military devices. Backed by Darpa funding, ADT will integrate UNCD oscillators and resonators directly onto telecommunication chips, which should give mobile communication devices much higher data rates.