Title :
Nb-based SIS mixer in the 800 GHz band
Author :
Noguchi, Takashi ; Maezawa, Hiroyuki ; Shi, Sheng-Cai ; Yamamoto, Satoshi
Author_Institution :
Nobeyama Radio Obs., Nagano, Japan
fDate :
3/1/2001 12:00:00 AM
Abstract :
We have built a waveguide SIS mixer with Nb-based parallel-connected twin junctions at 800 GHz which is above the gap frequency of Nb (690 GHz). Heterodyne mixing was performed at 810 GHz and a receiver noise temperature of 580 K (DSB), which includes noise contributions due to a vacuum window and a beam splitter, was achieved using Nb/AlOx/Nb junctions with Nb striplines. The performance of this mixer is quite good and it is shown that efficient mixing in Nb-based SIS junctions is still possible above the gap frequency, SIS mixers with Al striplines have also been fabricated and good DC I-V characteristics have been observed. Heterodyne measurements of these mixers are now under preparation
Keywords :
aluminium compounds; niobium; strip line circuits; submillimetre wave mixers; submillimetre wave receivers; superconducting device noise; superconductor-insulator-superconductor mixers; 800 GHz; 800 GHz band; 810 GHz; Al; Al striplines; DC I-V characteristics; Nb striplines; Nb-AlO-Nb; Nb-based parallel-connected twin junctions; Nb/AlOx/Nb junctions; Nb/AlOx/Nb waveguide SIS mixer; beam splitter; gap frequency; heterodyne mixing; noise contributions; receiver noise temperature; vacuum window; Artificial intelligence; Frequency; Niobium; Observatories; Stripline; Surface resistance; Telephony; Temperature; Waveguide discontinuities; Waveguide junctions;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
