A noise reduction design for IMPATT oscillators

This paper describes a technique for achieving considerably lower noise figures for IMPATT oscillators than have been previously reported. With these devices used as local oscillators, receiver noise figures in X band within 10 dB (single ended mixer 30 mc IF) and 0.2 dB (balanced mixer, 30 mc IF) of those produced with a klystron local oscillator have been obtained. The technique also results in a low oscillator pushing figure and an accompanying improvement in the spectrum of the device when pulsed. No external cavity stabilization is involved, and the oscillator consists only of a diode and a fundamental mode cavity.