自動化非接觸式介電係數感測系統設計與驗證

Design and Verification of An Automated Non-contact Dielectric Sensor System

黃聖勳(Sheng-Hsun Huang)

指導教授 ： 林啟萬

國立臺灣大學/電機資訊學院/生醫電子與資訊學研究所/碩士(2024年)

https://doi.org/10.6342/NTU202403311

摘要

由於生技製藥產業的發展和大眾對健康的重視，非接觸式、即時且精準的微波感測器在生醫工程中的應用變得越來越重要。透過分析微波波段電磁波與物質互動的訊號，可以進行物質介電係數的量測。
本研究將基於LC 振盪架構之介電係數感測器與微控制器整合，開發自動化非接觸式介電係數感測系統。在設計中，以微控制器中的計數器、SAR ADC 獲取振盪器的頻率與振幅訊號值，並對其以數位濾波器降低雜訊的影響。透過基於LC 振盪器的介電係數感測器的數學模型分析量測數據，可得到待測物的複數介電係數。本研究設計了不同的量測平台並建立量測流程，以降低環境影響與人為操作誤差。藉由分析量測得到的數據，對此系統的感測性能與即時量測功能進行驗證。
在靜態量測結果中，顯示此感測系統對不同樣本具有顯著的辨識能力，並且與折射率計、向量網路分析儀的量測結果呈現高度相關。在微流道動態量測結果中，顯示感測系統能即時反映反應區域的變化，驗證了其即時量測特性，並展現其對微量樣本的感測潛力。

關鍵字

介電係數 ； LC 振盪器 ； 生醫感測器 ； 指叉型電極

並列摘要

Due to the development of the biopharmaceutical industry and the increasing public concern for health, the application of non-contact, real-time, and precise microwave sensors in biomedical engineering is becoming increasingly important. By analyzing the interaction signals between microwave electromagnetic waves and materials, the dielectric constant of substances can be measured.
This study integrates an LC oscillator-based dielectric constant sensor with a microcontroller to develop an automated non-contact dielectric sensor system. In the our design, the frequency and amplitude signal values of the oscillator are obtained using the microcontroller’s counters and SAR ADC, with digital filters applied to reduce noise interference. The measurement results are analyzed using a mathematical model based on the LC oscillator dielectric sensor to obtain the complex dielectric constant of the material under test. Various measurement platforms were designed and measurement procedures established to minimize environmental impact and artifact. Through the analysis of measurement data, the sensing performance and real-time measurement capabilities were validated.
The static measurement results showed that this dielectric sensor system has significant discrimination capabilities for different samples and is highly correlated with the results from refractometers and vector network analyzers. In the dynamic measurement results using a microfluidic system, the dielectric sensor system demonstrated the ability to reflect changes in the reaction region in real-time, verifying its real-time characteristics and its potential for sensing small-volume samples.

並列關鍵字

Dielectric constant ； LC oscillator ； Biosensor ； Interdigital electrode viii

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