Theory of Noise and Transfer Properties of IMPATT Diode Amplifiers

A theory is formulated which describes quantitatively the noise and transfer properties of IMPATT diode reflection-type negative resistance amplifiers. This theory is based on the method used in the large-signal theory of noise in IMPATT diode oscillators by the present authors. The theory takes into account the signal dependence of the noise generation in the diode, the noise and/or modulation present in the input signal, and also the intermodulation effects occurring between the various frequency bands. The equations are conveniently arranged in matrix form; such a formulation makes it easier to obtain quantitative results in terms of measurable noise and modulation parameters. Agreement between measured and theoretically predicted AM and FM noise of injection-locked oscillators is good. The usefulness of the theory is illustrated by results of calculations on minimum attainable noise of a given amplifier, maximum noise allowable on the input signal, AM-FM conversion, phase distortion, bias modulation, and the correlation between various types of noise.