AlGaN/GaN high electron mobility transistor oscillator for high temperature and high frequency

Abstract A high‐temperature 2.1 GHz oscillator based on a AlGaN/GaN high electron mobility transistor (HEMT) is successfully designed, implemented, and characterised for the first time. The system is explicitly designed such that the final circuit consists of a single transistor bonded to a printed circuit board (PCB), and no further passive components besides the transmission lines to attach the connectors are used. Extensive characterisation of the high electron mobility transistor has been carried out up to 300∘C in order to extract large‐ and small‐signal models. Since the system does not rely on passive tolerances and a specific model of the used transistor has been extracted, a sustainable oscillation of the design at high temperature is assured. The capabilities of the designed circuit are verified by measurements up to 230∘C, showing a promising performance with around 0 dBm output power and a phase noise of −74 dBc/Hz at 1 MHz offset at the highest characterised temperature