Very tiny RF transistor made from graphene
Sweden’s Chalmers mixes up smaller, faster microwave electronics
Researchers at Chalmers University in Sweden have demonstrated a graphene-based transistor design that allows more compact RF mixer processing.
Not only would the technology permit more compact RF electronics: reducing the size of electronics also allows circuits to run faster – in the case of the Chalmers G-FET (graphene field-effect transistor), applications could reach up into the terahertz range.
While of limited use in consumer data applications, terahertz systems are important in radar, radio astronomy, and process monitoring, all of which use large arrays of RF mixers.
Graphene’s attraction in such applications is that it is electrically symmetrical, able to act either as an electron carrier or a hole carrier, meaning that a single G-FET is able to act as a mixer without requiring the feeding circuits used in current designs.
The Chalmers G-FET acts as a subharmonic mixer, which helps it meet another challenge of terahertz processing – the lack of oscillators able to drive THz circuits at suitable power. The subharmonic mixer only needs half the local oscillator frequency to operate. ®