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Proceedings Paper

Direct detection with Nb-based tunnel junctions at 74 GHz
Author(s): J. Mees
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Paper Abstract

Apart from the great success of SIS-junctions as mixers in heterodyne receivers there are several other reasons to intensify investigations of SIS-junctions as direct detectors. These devices can be produced as single junctions and arrays for use. in waveguide systems or in planar antennas by standard lithographic techniques. Impedance matching structures and filter elements can be incorporated easily. Recent developments1,2 in junction technology show strong improvements of junction performance. Areas of 0.5μm2 and leakage currents as low as 50nA have been realized. Since the final sensitivity (NEP) of SIS-junctions as direct detectors is limited ultimately by the shot noise of the bias current (NEP∼√IL), a low leakage current IL, is highly important for these devices. Using these improved SIS-junctions, NEP's down to 10-17W/√Hz seem to be possible with He4-cooled devices. A crude estimate for the time constant of a SIS-direct detector yields the inverse of the gap frequency h/∆ or the sumgap frequency h/2∆, which gives very small values of 1 − 10psec.

Paper Details

Date Published: 1 October 1991
PDF: 2 pages
Proc. SPIE 1576, 16th International Conference on Infrared and Millimeter Waves, 157633 (1 October 1991); doi: 10.1117/12.2297824
Show Author Affiliations
J. Mees, Max-Planck-Institut für Radioastronomie (Germany)

Published in SPIE Proceedings Vol. 1576:
16th International Conference on Infrared and Millimeter Waves
Minh Quang Tran, Editor(s)

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