The Josephson Two-Terminal-Pair Impedance Bridge

TitleThe Josephson Two-Terminal-Pair Impedance Bridge
Publication TypeJournal Article
Year of publication2010
AuthorsLee, J., J. Schurr, J. Nissilä, L. Palafox, and R. Behr
JournalMetrologia IOP
Date publishedsubmitted 03/10

We present the connection of two programmable Josephson arrays generating
synchronous waveforms to measure impedance ratios — The Josephson two-terminalpair impedance bridge. This approach is more flexible than conventional bridges at the same level of uncertainty. The Josephson bridge can measure over a wider frequency range, over a wider range of impedance ratios than conventional two-terminal-pair bridges. Furthermore, the phase angle between the two impedances can take any value. As a first application, we present measurements of a 1:1 resistance ratio at the 10-kΩ level in the frequency range between 25 Hz and 10 kHz. The uncertainties are better than a few parts in 108 and hence comparable to those of conventional impedance bridges. Quantization at up to 10 kHz was confirmed by varying the bias current of the Josephson arrays resulting in constant resistance ratios within the measurement resolution.