Receivers based upon the superconductor-insulator-superconductor (SIS) quasiparticle tunnel junction mixer have now surpassed conventional Schottky-diode receivers in sensitivity, and are having an immediate impact on millimeter-wavelength astronomy. Even so, much further research is needed before this technology can reach its full potential. This award supports theoretical and experimental study of SIS junctions as millimeter- and submillimeter-wave detectors. The research seeks a better analytical and intuitive understanding of SIS mixers and related phenomena, relying on the quantum theory of mixing, with special attention to noise phenomena, optimum mixer design parameters, tuning structures, and to investigating the appropriate capacitance for SIS junctions.
