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

Low noise receivers play critical role in space applications. Thin film high-critical-temperature-superconducting (HTS) passive circuits were combined with GaAs microwave devices to achieve ultra low noise and small size 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 superconductor/semiconductor 7.4 GHz microwave receiver. When cooled to 77 K, the downconverter plus cables inside a cryogenic refrigerator had a noise figure of approximately 0.7 dB with conversion gain of 18 dB. In addition to reduce noise figure, advantages of small size and low power consumption are observed due to the use of HTS circuits in the downconverter.< >