SOME RECENT DEVELOPMENTS IN THE DESIGN OF SIS MIXERS

SIS mixers in which superconducting tuning elements are integrated with the tunnel junctions have resulted in very low noise heterodyne receivers in the range 68-260 GHz. Above ∼120 GHz the need for extremely small reduced-height waveguides is avoided by mounting the SIS junctions in a suspended-stripline circuit coupled to a full-height waveguide by a broadband probe. The special characteristics of coplanar transmission line permit the design of SIS mixers with low parasitic reactances. Such a mixer operates over the full WR-10 band (75-110 GHz) without mechanical tuners. © 1990 Plenum Publishing Corporation.