IEEE Transactions on Applied Superconductivity

Low-noise slot antenna SIS mixers

Jonas Stasys Zmuidzinas, N. G. Ugras, D. Miller, Michael C. Gaidis, Henry George LeDuc, J. A. Stern

Published Jun 1, 1995• 56 citations

Abstract

We describe quasi-optical SIS mixers operating in the submillimeter band (500-750 GHz) which have very low noise, around 5 h/spl nu//k/sub B/ for the double-sideband receiver noise temperature. The mixers use a twin-slot antenna, Nb/Al-Oxide/Nb tunnel junctions fabricated with optical lithography, a two-junction tuning circuit, and a silicon hyperhemispherical lens with a novel antireflection coating to optimize the optical efficiency. We have flown a submillimeter receiver using these mixers on the Kuiper Airborne Observatory, and have detected a transition of H/sub 2//sup 18/O at 745 GHz. This directly confirms that SIS junctions are capable of low-noise mixing above the gap frequency.>

DOI: 10.1109/77.403236

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