Design and performance of low-noise hybrid superconductor/semiconductor 7.4 GHz receiver downconverter

Abstract

Low noise receivers play critical role in space applications. Thin film high-crtical -temperaturesuperconducting (HTS) passive circuits were combined with GaAs microwave devices to achieve ultra low noise and small sue receiver downconverter at 77 K HTS pre-select filter, a cryogenic mixer, and a hybrid oscillator with an HTS resonator were designed, fabricated and interconnected to produce a low-noise hybrid superconductorlsemiconductor 7.4Ghz microwave reciever.When cooled to 77K, the downconverter plus cables inside a cryogenic refrigerator had a noise figure of approximately 0.7dB with convdersion gain of 18 dB. In addition to reduce noise figure, advantages of small sue and low power consumption are obsereved due to the use of HTS circuits in the downconverter.