共面波導天線型生物感測器之設計與應用

Abstract

隨著生物醫學感測應用的增加，創新的技術和架構必須不斷推陳出新。為了改善傳統方法必須依賴螢光標示與電化學反應才能進行感測應用的侷限性，本研究 提出非侵入式近場電磁感應技術，實作一以天線設計技術為基礎之生物感測器， 探討天線與不同介電性質樣品間的近場電磁相互作用，藉由天線和測試樣品之間的電磁耦合分析，達到無需進行螢光標示或化學反應即可分辨不同介電性質差異性之目標。 此天線感測器的設計採用共面波導(coplanar waveguide)饋入機制，此機制之特性為透過表面微帶傳輸線(surface-strip transmission line)將接地導體面(ground plane)緊鄰並平行於中心導體兩側，再由兩個溝槽區隔位於介質基板的同一平面。相較於傳統的微帶線技術，共面波導機制擁有多種優勢，如可將待測樣品放置或接觸在感測器背面以進行量測，可提供非破壞性的測量功能。共面波導天線型感測器的設計首先透過Ansoft HFSS模擬軟體進行模型建立與模擬，再利用厚度為0.8毫米的FR-4基板進行實作，具有低成本之實作優勢，成品尺寸為(20x20x0.8)立方毫米。 本研究應用兩種測量方法進行研究成果測試，第一種方法將液體樣本滴入共面波導天線感測器表面，以塑膠貼紙製成的樣品界限區域內；第二種方法則將液體樣本流過共面波導天線感測器背面的微流道。所有的測量過程均使用Agilent E5071B網絡分析儀，以不同濃度的乙醇、甲醇、葡萄糖、氯化鈉(食鹽)，及含有不同成份的日常飲料如啤酒、紅酒和烈酒等液體樣本進行量測。量測結果證實本研究所發展的共面波導天線型生物感測器，可成功辨別不同液體的介電特性，有助未來非侵入式生物醫學感測之應用。

As the demand for biomedical sensing applications increase, an innovative techniques and architectures are required. To overcome the limitations of traditional methods, noninvasive near-filed electromagnetic sensing technique is proposed for biomedical applications. An antenna based biosensor is developed to investigate the near-field electromagnetic interaction between antenna and sample with different dielectric properties. These dielectric properties can be determined by analyzing the electromagnetic coupling between the antenna and the test samples without labeling or chemical reaction. The antenna biosensor is developed by applying the coplanar waveguide (CPW) feeding mechanism, a surface-strip transmission line (TL), which consists of a strip on thin metallic film deposited on the surface of a dielectric slab with two ground electrodes running adjacent and parallel to the strip on the same surface. The coplanar waveguide offers a variety of advantages over the conventional micro-strip line, it can be placed conveniently in contact with one side of the test material and therefore provide non-destructive measurements. The coplanar waveguide (CPW) antenna biosensor is modeled and simulated with Ansoft HFSS and fabricated on inexpensive FR-4 substrate of thickness 0.8 mm, the overall dimension of the antenna biosensor is (20x20x0.8)mm3. Two measurement methods were applied in this research, one supply the sample to the surface of the antenna with a tape boundary, and another by a fluidic channel attached on the backside of the coplanar waveguide antenna biosensor, all measurements were taken by Agilent E5071B Network Analyzer. Experimentally validated the liquid samples with different dielectric properties, different concentrations of ethanol, methanol, glucose, sodium chloride solution, and different daily beverage like beer, red wine and liquor were measured and determined with the proposed coplanar waveguide antenna biosensor. The results exhibit the potential applications in bio-sensing.