• Title/Summary/Keyword: 튜닝폭 피드백 시스템

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Concentration of Sodium Chloride Solutions Sensing by Using a Near-Field Microwave Microprobe (비접촉 근접장 마이크로파 현미경을 이용한 NaCl 용액의 농도 측정)

  • Kim, Song-Hui;Yoon, Young-Woon;Babajanyan, Arsen;Kim, Jong-Chul;Lee, Kie-Jin
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.1
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    • pp.23-30
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    • 2007
  • We observed the NaCl concentration of solutions using a near-field microwave microprobe(NFMM). Instead of the usual technique, we take advantage of the noncontact evaluation capabilities of a NFMM. A NFMM with a high Q dielectric resonator allows observation of small variations of the permittivity due to changes in the NaCl concentration. The changes of NaCl concentration due to a change of permittivity of the NaCl solution were investigated by measuring the microwave reflection coefficient $S_{11}$ of the resonator. The NaCl sensor consisted of a dielectric resonator coupled to a probe tip at an operating frequency of about f=4 GHz. The change of the NaCl concentration is directly related to the change of the reflection coefficient due to a near field electromagnetic interaction between the probe tip and the NaCl solution. In order to determine the probe selectivity, we measured a mixture solution of NaCl and glucose.