Title :
Quasi-optical SIS mixers with normal metal tuning structures
Author :
Mei Bin ; Gaidis, M.C. ; Zmuidzinas, J. ; Phillips, T.G. ; LeDuc, H.G.
Author_Institution :
Downs Lab. of Phys., California Inst. of Technol., Pasadena, CA, USA
fDate :
6/1/1997 12:00:00 AM
Abstract :
We recently reported (1996) a quasi-optical SIS mixer which used Nb/Al-oxide/Nb tunnel junctions and a normal-metal (Al) tuning circuit to achieve an uncorrected receiver noise temperature of 840 K (DSB) at 1042 GHz. Here we present results on several different device designs, which together cover the 300-1200 GHz frequency range. The mixers utilize an antireflection-coated silicon hyper-hemispherical lens, a twin-slot antenna, and a two-junction tuning circuit. The broad-band frequency response was measured using Fourier transform spectrometry (FTS), and is in good agreement with model calculations. Heterodyne tests were carried out from 400 GHz up to 1040 GHz, and these measurements agree well with the FTS results and with calculations based on Tucker´s theory (1985).
Keywords :
Fourier transform spectroscopy; alumina; circuit tuning; frequency response; niobium; submillimetre wave mixers; submillimetre wave receivers; superconducting device noise; superconducting device testing; superconductor-insulator-superconductor mixers; 300 to 1200 GHz; Al; Fourier transform spectrometry; Nb-AlO-Nb; Nb/AlO/sub x//Nb tunnel junctions; Tucker theory; antireflection-coated Si hyper-hemispherical lens; broad-band frequency response; heterodyne tests; normal metal tuning structures; quasi-optical SIS mixer; receiver noise temperature; twin-slot antenna; two-junction tuning circuit; Antenna measurements; Circuit noise; Circuit optimization; Fourier transforms; Frequency measurement; Frequency response; Lenses; Niobium; Silicon; Temperature;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
