LOW-NOISE MICROWAVE AMPLIFIER THAT USES SUPERCONDUCTOR-INSULATOR-SUPERCONDUCTOR JUNCTION

摘要

To realize a low-noise amplifier which has a low noise temperature and a wide frequency band, and which is easy to cool and retain a low temperature with an ultra low-power consumption property even if a plurality of amplifiers are mounted.SOLUTION: A low-noise microwave amplifier is arranged by use of a superconductor-insulator-superconductor junction (SIS). The low-noise microwave amplifier comprises a circuit arranged by cascade-connecting two SIS quasiparticle mixers (frequency mixer), in which the first quasiparticle mixer includes in a first frequency mixing action to be performed using a first local oscillation signal having a frequency of no smaller than double the frequency of input signals to the first quasiparticle mixer, and the second quasiparticle mixer involves in a second frequency mixing action to be performed using a second local oscillation signal having a frequency of no larger than double the frequency of input signals to the second quasiparticle mixer. By extracting, from a plurality of signals produced by the first and second frequency mixing actions, signals of a frequency band equal to or under a frequency band of signals before being subjected to the first and second frequency mixing actions by use of a transmission line property or a wave filter, signal amplification on a conversion gain by frequency conversion is performed.SELECTED DRAWING: Figure 5