Microwave performance of YBa/sub 2/Cu/sub 3/O/sub 7-x/ resonators coupled to single-junction SQUIDs

Abstract

The effects of microwave current and dc magnetic field on quality factor and resonant frequency at 3 GHz of planar resonators, which were differently coupled to hysteretic microwave SQUIDs, are discussed. The dissipative response is analyzed in terms of a single-junction SQUID, and its coupling to a resonant tank circuit. The temperature dependences and field periodicities of all relevant parameters are discussed, and conditions for optimized operation are deduced. The results indicate potential for further improvement of the performance of microwave SQUID magnetometers.

High-transition-temperature superconducting quantum interference devices

“…(2.15), further reductions in noise require highfrequency operation, but it then becomes difficult to achieve the required high values of Q with lumped circuits. As a result, devices operating at higher frequencies have involved various kinds of microwave resonators Zhang, Mü ck, Bode et al, 1992Hein et al, 1995). Zhang, Mü ck, Bode et al (1992) described an S-shaped microstrip resonator with the 100 ϫ100 m 2 SQUID loop in its central region [ Fig.…”