US scientists, armed with nothing more complicated than a pair of tweezers, have built a working radio receiver from a sheet of graphene.
The engineering significance of the finding lies in the fact that the set up does not suffer from parasitic capacitance, the bane of the lives of electrical engineers once the components get small enough, and close enough together. This is not a problem for the University of Columbia team because their design effectively causes the various bits of parasitic capacitance to cancel each other out.
Commercially the news is good, too, since the scientists also say that with smaller slivers of graphene they should be able to get a receiver working at GHz frequencies – news that is certain to attract the attention of mobile phone companies everywhere.
The researchers stretched a piece of graphene between two electrodes and over a third (MIT rather wonderfully calls it a graphene trampoline here). They passed a direct current through the sheet and applied RF voltage on top, and they found that they sheet
“resonates when blasted with a voltage changing at radio frequency signals and that this can be easily measured by monitoring the capacitance between the sheet and the third electrode below the sheet” per MIT’s technology review.
As ever with these things, the operating temperature is low – 77K – and the manufacturing process (tweezers) is not easily scalable. But the researchers seem to think these are problems that can be addressed.
You can read the paper at Arvix.org, here.