Phase-locked Gunn oscillator at 21 GHz.

Restricted Access.A phase-locked Gunn Oscillator at 21 GHz for local oscillator application in a low-noise radio astronomy receiver is described. The oscillator gives a maximum CW power output of 60 mW, bias-tuning range of 40 MHz, and DSB AM noise of -140 dBc in 1-kHz bandwidth at 1.4 GHz away from the carrier. The phase lock scheme developcd for the Cunn oscillator is highly versatile and can be used for phase locking a variety of solid-state millimetre-wave sources