A hybrid superconductive/semiconductive microwave receiver

A 6 GHz hybrid superconductive/semiconductive microwave receiver (HSSMR) has been developed. It consists of an HTS microstrip preselect filter, a cryogenic LNA, a commercially available off-the-shelf mixer, and a superconducting local oscillator (LO). The operating bandwidth is 500 MHz, which is centered at an RF frequency of 5.9 GHz and a corresponding IF frequency of 4.483 GHz. Downconversion is facilitated by a 10.383 GHz LO. The oscillator incorporates an HTS/sapphire resonator with a measured unloaded Q of 98100, at 77 K. The entire receiver is cooled to an operating temperature of 77 K. The measured performance is given for each of the components and for the overall receiver. The resultant receiver conversion gain is 27.5 dB and the associated noise figure is less than 0.7 dB.