Applied Physics Letters

Josephson tunnel junction microwave attenuator

V. P. Koshelets, S. V. Shitov, А. В. Щукин, Andrey M. Baryshev, Lyudmila V. Filippenko, Georg Fischer, J. Mygind

Published Dec 6, 1993• 3 citations

Abstract

A new element for superconducting electronic circuitry—a variable attenuator—has been proposed, designed, and successfully tested. The principle of operation is based on the change in the microwave impedance of a superconductor-insulator-superconductor (SIS) Josephson tunnel junction when dc biased at different points in the current-voltage characteristic. Both numerical calculations based on the Tien–Gordon theory and 70-GHz microwave experiments have confirmed the wide dynamic range (more than 15-dB attenuation for one stage) and the low insertion loss in the ‘‘open’’ state. The performance of a fully integrated submillimeter receiver circuit which comprises a flux–flow oscillator (FFO) as local oscillator, a superconducting variable attenuator, and a microwave SIS detector with tuned-out capacitance is also reported.

DOI: 10.1063/1.110203

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