A broadband low noise SIS receiver for submillimeter astronomy

A quasioptical heterodyne receiver is described that uses a PbInAu alloy superconductor-insulator-superconductor (SIS) tunnel junction as the detector and a planar logarithmic spiral antenna for the radiofrequency (RF) coupling. Noise measurements were made at frequencies between 115 GHz and 761 GHz, yielding double-sideband noise temperatures ranging from 33 K to 1100 K.<<ETX>>