Chalmers graphene mixer opens up THz possibilities

http://www.zdnet.co.uk/blogs/qubits-and-pieces-10017876/swedish-teams-graphene-mixer-opens-up-thz-possibilities-10025129/
Researchers at Sweden’s Chalmers University have built a CMOS compatible graphene based electronic mixer – a device that combines multiple input signals into one or two composite outputs – that already works at microwave frequencies and could be extended to the terahertz range.

Jan Stake, professor of the research team says that the performance of the mixer can be improved by further optimising the circuit, and improving the on-off ratio. "Using a G‐FET in this new topology enables us to extend its operation to higher frequencies, thereby exploiting the exceptional properties of graphene. This paves the way for future technologies operating at extremely high frequencies."

As per this announcement on the university’s website, such a high frequency component could have applications in security radar systems, radio astronomy and environmental monitoring; all area where large arrays of highly sensitive, and compact mixers are required.

The breakthrough depends on the ability of graphene to switch between hole and electron carriers via the field effect. Because of this, the researchers built the mixer using only one transistor, making it much more compact than traditional mixers. This opens up the possibility of “advance sensor arrays for example for imaging at millimetre waves and even sub millimetre waves as G-FET technology progress” according to the announcement.