TY - JOUR
T1 - Determination of quality factor for highly overcoupled EPR resonators
AU - Ohba, Yasunori
AU - Watanabe, Chika
AU - Nakazawa, Shigeaki
AU - Yamauchi, Seigo
N1 - Funding Information:
Acknowledgments We would like to thank Dr. Ono for providing the γ-irradiated quartz sample and helpful discussion. This work was partly supported by Grant-in-Aid for Scientific Researches no. 18559001 and no. 19350003 from the Ministry of Education, Science, Culture, and Sports (Japan) and by the Centers of Research Excellence in Science and Technology program of the Japanese Science and Technology Agency.
PY - 2010
Y1 - 2010
N2 - We reported determination of the loaded quality factor (Q) of highly overcoupled (dielectric, loop-gap, and cavity) resonators used in time-domain electron paramagnetic resonance. We introduced a microwave absorber into resonators and achieved critical-coupling. Due to the deep "Q-dip" of critical-coupling, we can easily determine the loaded Q as low as 10. The loaded Q of resonators with and without the microwave absorber was examined under various overcoupling conditions. We found that the radiation Q (Qr) can be calculated from the loaded Q of the resonator that contains the microwave absorber. We proposed a simple model that represents the loaded Q of the overcoupled resonator in terms of two parameters, Q0 and Qr. Q0 is the effective unloaded Q of the resonator determined for the critically coupled resonator without the microwave absorber and is independent of a degree of coupling. The model can be applied to overcoupling in which the coupling parameter (Q0/Qr) is in the range of 1 to ca. 20.
AB - We reported determination of the loaded quality factor (Q) of highly overcoupled (dielectric, loop-gap, and cavity) resonators used in time-domain electron paramagnetic resonance. We introduced a microwave absorber into resonators and achieved critical-coupling. Due to the deep "Q-dip" of critical-coupling, we can easily determine the loaded Q as low as 10. The loaded Q of resonators with and without the microwave absorber was examined under various overcoupling conditions. We found that the radiation Q (Qr) can be calculated from the loaded Q of the resonator that contains the microwave absorber. We proposed a simple model that represents the loaded Q of the overcoupled resonator in terms of two parameters, Q0 and Qr. Q0 is the effective unloaded Q of the resonator determined for the critically coupled resonator without the microwave absorber and is independent of a degree of coupling. The model can be applied to overcoupling in which the coupling parameter (Q0/Qr) is in the range of 1 to ca. 20.
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U2 - 10.1007/s00723-009-0066-7
DO - 10.1007/s00723-009-0066-7
M3 - Article
AN - SCOPUS:71249134401
VL - 37
SP - 781
EP - 794
JO - Applied Magnetic Resonance
JF - Applied Magnetic Resonance
SN - 0937-9347
IS - 1
ER -