Low phase noise oscillator with flicker (1/f) noise suppression circuit

The author describes a new and simple oscillator circuit enhancement, demonstrated with a 10-GHz Gunn oscillator, that suppresses the generation of flicker (1/f) noise, which is the major contributor to phase noise close to the carrier. The suppression of 1/f noise is accomplished by a circuit, integral to the Gunn oscillator, that reduces the oscillator pushing (frequency change with bias voltage) to zero. The technique is capable of 1/f noise suppression from the 1/f noise that is approximately 25 kHz for a Gunn diode to carrier frequency.<>