Title :
Low-noise slot antenna SIS mixers
Author :
Zmuidzinas, J. ; Ugras, N.G. ; Miller, D. ; Gaidis, M. ; LeDuc, H.G. ; Stern, J.A.
Author_Institution :
California Inst. of Technol., Pasadena, CA, USA
fDate :
6/1/1995 12:00:00 AM
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.<>
Keywords :
slot antennas; submillimetre wave antennas; submillimetre wave mixers; superconducting device noise; superconducting microwave devices; superconductor-insulator-superconductor mixers; 500 to 750 GHz; H/sub 2//sup 18/O transition; H/sub 2/O; Kuiper Airborne Observatory; Nb-AlO-Nb; Nb/Al-oxide/Nb tunnel junctions; antireflection coating; double-sideband receiver noise temperature; optical efficiency; optical lithography; quasi-optical SIS mixers; silicon hyperhemispherical lens; submillimeter receiver; twin-slot antenna; two-junction tuning circuit; Circuit noise; Circuit optimization; Lithography; Niobium; Optical mixing; Optical noise; Optical receivers; Optical tuning; Slot antennas; Temperature;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
