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Title: Regenerative Feedback Resonant Circuit to Detect Transient Changes in Electromagnetic Properties of Semi-Insulating Materials

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 7,000 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 107 - 108. 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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Publication Date:
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Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments, 84(8):Article No. 084703
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
Country of Publication:
United States
Feedback circuits; material resonators; multimodal sensors; cavity perturbation