SIS receivers for millimeter and submillimeter-wave detection

In this work we report the current status in our development of sensitive heterodyne detectors for efficient down-conversion of submillimeter-wave signals to D-band. These detectors use the strong non-linearity of Nb/Al-AlO/sub x//Nb tunnel junctions and employ preferably quasi-optical techniques to couple local-oscillator and radio-frequency signals to the superconducting junctions via a log-periodic antenna and hyper-hemispherical lens combination. Several devices have been fabricated and tested.