Title :
A low noise 230 GHz heterodyne receiver employing 0.25-μm2 area Nb-AlOx-Nb tunnel junctions
Author :
Kooi, Jacob W. ; Chan, M. ; Phillips, T.G. ; Bumble, B. ; LeDuc, H.G.
Author_Institution :
California Inst. of Technol., Pasadena, CA, USA
fDate :
5/1/1992 12:00:00 AM
Abstract :
The authors report recent results for a full-height rectangular waveguide mixer with an integrated IF matching network. Two 0.25 μm 2 Nb-AlOx-Nb superconducting-insulating-superconducting (SIS) tunnel junctions with a current density of ≈8500 A/cm2 and ωRC of ≈2.5 at 230 GHz have been tested. One of these quasiparticle tunnel junctions is currently being used at the Caltech Submillimeter Observatory in Hawaii. Detailed measurement of the receiver noise have been made from 200-290 GHz for both junctions at 4.2 K. The lowest receiver noise temperatures were recorded at 239 GHz, measuring 48 K DSB at 4.2 K and 40 K DSB at 2.1 K. The 230-GHz receiver incorporates a one-octave-wide integrated low-pass filter and matching network which transforms the pumped IF junction impedance to 50 Ω over a wide range of impedances
Keywords :
aluminium compounds; mixers (circuits); niobium; radio receivers; radiotelescopes; solid-state microwave circuits; submillimetre wave devices; superconducting junction devices; superconductive tunnelling; 200 to 290 GHz; 230 GHz; 4.2 K; Caltech Submillimeter Observatory; EHF; Nb-AlOx-Nb tunnel junction; SIS type; heterodyne receiver; integrated IF matching network; integrated low-pass filter; low noise; quasiparticle tunnel junctions; receiver noise; rectangular waveguide mixer; superconducting-insulating-superconducting; Current density; Impedance measurement; Josephson junctions; Noise measurement; Observatories; Rectangular waveguides; Superconducting device noise; Superconducting devices; Temperature distribution; Testing;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
