480 GHz oscillator with an InP Gunn device

An InP Gunn device with a graded doping profile was evaluated for third-harmonic power extraction around 480 GHz. The oscillator used the configuration of a WR-6 waveguide cavity for the InP Gunn device, two back-to-back waveguide transitions, WR ?? 3 1.5 and WR ?? 1.7 3, to block fundamental and second-harmonic frequencies, and WR-6 waveguide spacers to optimise the location of the reactive termination at the fundamental frequency. With 350 ??m-thick spacers, the oscillator yielded an RF output power of more than 85 ??W at 479.01 GHz.