Title :
Accurate noise measurements of superconducting quasiparticle array mixers
Author :
McGrath, W. ; Raisanen, Antti ; Richards, P.L. ; Harris, R.E. ; Lloyd, F.L.
Author_Institution :
University of California, Berkeley, California
fDate :
3/1/1985 12:00:00 AM
Abstract :
We have constructed a 30-40 GHz test apparatus which allows us to measure the noise temperatures of SIS mixers with an accuracy of better than ±1K. This is a factor of six improvement over earlier measurements. The most accurate measurement made thus far of a mixer which uses a single Pb-alloy junction yielded Tm= 9.2 ± 0.9 K; and mixer gain: Gm= 0.240 ± 0.005. In addition, SIS mixers employing arrays of N = 1, 5, 10, 25, and 50 tunnel junctions in series have been tested. The input power required to saturate the array mixers was found to increase as N2and the gain and noise temperature of the array mixers were independent of N.
Keywords :
Josephson device mixers/frequency converters; Measurement noise; Noise measurement; Superconducting transmission lines; Extraterrestrial measurements; Frequency; Gain measurement; Noise measurement; Quantum mechanics; Receivers; Superconducting device noise; Temperature measurement; Testing; Tunneling;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.1985.1063708