Millimeter wave mixing with submicron area Nb tunnel junctions

Abstract
Submicron area Nb edge tunnel junctions have been fabricated yielding devices with RC times of 10−13 s. Tested as quasiparticle mixers at 55 GHz, they yielded conversion loss of 6.4 db SSB and a noise temperature ?27 K. A gain of 1.4 db with a noise temperature of 145 K was also achieved but was attributed to the Josephson effect.