A low-noise up-converter parametric amplifier

Abstract

The theoretical and experimental performance is presented of a low-noise up-converter that uses a back-biased, diffused-junction diode. Some results of the theoretical analysis are described to show how the gain and noise figure of the amplifier depend on the diode loss, available capacitance variation, and generator and load terminations. It is also shown that when power is dissipated in the diode at the lower sideband frequency, the gain of the up-converter is greatly increased while the noise figure is relatively unaffected. The construction of an experimental up-converter is described as well as the instrumentation and techniques used in measuring its gain and noise figure. When no power is dissipated in the diode at the lower sideband frequency, it is found that, for an input signal frequency of 410 Mc and an output up-converter frequency of 9227 Mc, a gain of12.4 \pm 0.5db and a noise figure of about 0.9 db can be obtained. When a large amount of power is dissipated at the lower sideband frequency, it is found that the gain is about 20 db and the noise figure is about 1.0 db.