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.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
