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Updated: May 8, 2026

Fabrication and Characterization of Superconducting Resonators
Published on: May 21, 2016
Regenerative feedback resonant circuit to detect transient changes in electromagnetic properties of semi-insulating
A Mark Jones1, James F Kelly, Ronald H Severtsen
1Pacific Northwest National Laboratory, Richland, Washington 99352, USA.
Abstract:
A prototype regenerative feedback resonant circuit has been developed for measuring the transient spectral response due to perturbations in properties of various electromagnetic materials. The circuit can accommodate a variety of cavity resonators, shown here in the 8 GHz range, with passive quality factors (Qstat) as high as 7000 depending upon material loading. The positive feedback enhanced dynamic quality factors (Qdyn) of resonator∕material combinations in the regenerative circuit are on the order of 10(7)-10(8). The theory, design, and implementation of the circuit is discussed along with real-time monitored example measurements of effects due to photon-induced charge carriers in high-resistivity silicon wafers and magnetic-field induced perturbations of yttrium-iron garnet.
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