Title :
A 125-180 GHz fixed-tuned SIS mixer for radioastronomy
Author :
Karpov, A. ; Blondel, J. ; Pasturel, P. ; Gundlach, K.H.
Author_Institution :
Inst. de Radioastron. Millimetrique, Domaine Univ., France
fDate :
6/1/1997 12:00:00 AM
Abstract :
An ultra low noise fixed-tuned SIS mixer covering an instantaneous band of 45% around 150 GHz has been developed for radioastronomy. A new type of coplanar tuning circuit for the SIS junction is introduced. The Nb/Al oxide/Nb junctions are 2 /spl mu/m/sup 2/ with critical Josephson current density of 4.2 KA/cm/sup 2/. The minimum DSB mixer noise is 11 K. The minimum DSB receiver noise is 19 K, while the average noise is 25 K in the 130-175 GHz range with a 1 GHz IF band. A speedup of the observations by a factor 2-3 is possible with the new receiver at 30 m IRAM radiotelescope.
Keywords :
circuit tuning; millimetre wave mixers; millimetre wave receivers; radioastronomical techniques; superconducting device noise; superconducting microwave devices; superconductor-insulator-superconductor mixers; 125 to 180 GHz; DSB mixer noise; DSB receiver noise; IF band; IRAM radiotelescope; Nb-AlO-Nb; Nb/Al oxide/Nb junction; coplanar tuning circuit; critical Josephson current density; radioastronomy; ultra low noise fixed-tuned SIS mixer; Circuit noise; Conductors; Current distribution; Magnetic field measurement; Power cables; Superconducting cables; Superconducting device noise; Superconducting devices; Superconducting transmission lines; Testing;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
