本論文基於射頻振盪器設計一新型微流體介電係數感測器，並使用酒精水溶液與葡萄糖水溶液作為待測液體(liquid under test, LUT)，進行感測器效能驗證。論文中設計了兩種不同的感測元件，分別為經改良之共面帶線共振器(modified coplanar strip resonator, MCSR)及T型LC共振器(T-shape LC resonator, TLCR)，用以聚焦電場於感測區域內，並同時作為感測振盪器之頻率選擇元件。此外，兩種感測振盪器分別與毛細管和二甲基矽氧烷(polydimethylsiloxane, PDMS)微流體裝置整合，並比較液體介電係數量測之準確度。當不同待測液體注入微流體裝置時，振盪器的振盪頻率與功率將發生改變，輸出訊號經由頻率解調器轉換成電壓訊號。在進行待測液體量測前，感測器使用已知介電係數液體進行校準，並使用曲線擬合將介電係數對應到電壓訊號。在酒精水溶液及葡萄糖水溶液作為待測液體的實驗中，本論文感測器的測量結果與市售介電係數量測儀器所獲得的結果吻合。本論文所提出之微流體介電係數感測器具有靈敏度高、電路結構簡易等優點，且可自行產生射頻測試源，未來可進一步應用於實際的生物醫學或食品工業等領域。

This thesis designs a new microfluidic dielectric sensor based on a radio-frequency oscillator. The ethanol-water mixtures and glucose solution are used as the liquid under test (LUT) to verify the sensor's performance. In this thesis, two different sensing elements are designed, namely MCSR (modified coplanar strip resonator, MCSR) and TLCR (T-shape LC resonator, TLCR), to concentrate the electric field in the sensing area and also serve as a frequency-selective element for oscillator design. In addition, two sensing oscillators were integrated with capillary and Polydimethylsiloxane (PDMS) microfluidic devices, respectively, and their measured dielectric measurement accuracy was compared. When different LUTs are injected into the microfluidic device, the oscillation frequency and power of the oscillator will change, and the output signal will be converted into a voltage signal through a frequency demodulator. Before measuring the LUT, the sensor is calibrated with a liquid of known dielectric constant, and curve fitting is used to map the dielectric constant to the voltage signal. In the experiment of ethanol-water mixtures and glucose solution as the LUTs, the measurement results of the sensor proposed in this thesis are consistent with the results obtained by the commercial dielectric probe kit. The microfluidic dielectric sensor proposed in this thesis has the advantages of high sensitivity, simple circuit structure, etc., and can generate a radio-frequency test source by itself. It can be further applied to the fields of biomedicine or the food industry in the future.

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