4 GHz low noise parametric amplifier

A low-maintenance 4-GHz parametric low-noise amplifier, suitable for use in ground stations operating with Intelsat satellites, is described. Features of the device include a Gunn oscillator operating at 11 GHz followed by an X4 multiplier, a long-term gain stability, and a compact 4-GHz circulator having a very low noise contribution and intrinsic rejection of spurious transmitter signals. Test results indicate that the amplifier may attain a noise temperature of 55 K, a low pump frequency (44 GHz) and, with a moderate amount of refrigeration, temperature of about 20 C in the microwave section.