本文提出一三環平面互補式開口環型諧振器(Triple-ring complementary split-ring resonators, TCSRR)感測曲面待測物(Material under test, MUT)特性之微波感測技術，透過多頻帶感測器能獲取更多待測物資訊，以平均或去極值等方法有效減少誤差。透過分析MUTs接觸TCSRR表面後，系統共振頻率的偏移趨勢，可反推出MUTs之特性，其可應用於生物組織量測或其他曲面材料之特性估測上。本文所提出方法相較傳統微波方法如自由空間傳輸法、開放共振腔法等，有不限制MUT大小與型態之優勢，並且可適用於不同曲度之MUT特性量測。根據量測結果，所提出方法在估測目標之兩類曲面MUTs：硬質(3D列印)、軟質(豬脂肪)之曲面MUTs特性，有相當高的準確度。在TCSRR與曲面MUTs中心對齊時，量測厚度2 mm、曲率半徑25、35 mm之硬質MUTs之厚度與曲率半徑估測誤差分別為0.12 mm、2.44 mm；而同樣大小規格的軟質MUTs之估測誤差則為0.18 mm、1.38 mm，以上之量測結果證實了所提出方法之可靠度與準確度。針對實際量測時可能出現的MUTs與TCSRR中心之錯位(Misalignment)，或兩者間不理想之空氣間隙對估測結果的影響有一系列的探討。量測結果顯示，由於TCSRR本身共振結構與電場分布特性，在與TCSRR傳輸線平行之錯位會對估測結果有嚴重影響；相反的，若是與在TCSRR傳輸線垂直方向錯位則仍有一定準確度。而關於空氣間隙之影響，與平面MUTs不同，曲面MUTs所受之空氣間隙對於估測結果影響並不如前者致命。此探討表明了使用TCSRR量測上的優勢與限制，對未來之應用提供了使用參考。總結所提出方法，其為曲面MUTs特性之估測提供了一全新且準確之測量方法，相 較其他微波方法，其應用範圍更廣、限制更少，且大大提升了量測各種曲面MUTs特性之可行性。

This thesis proposed a noncontact technique of estimating the curvature and thickness of curved materials based on triple-ring complementary split-ring resonators (TCSRR). The resonance frequency shift of the TCSRR is used to estimate the thickness and curvature of materials under test (MUTs). With multi-band sensing, more information of MUT can be obtained from the resonance frequencies and several results can be estimated. By averaging the results, the estimated errors are reduced. Compared with the traditional microwave method, the proposed method has the advantage of not limiting the size and type of MUTs. Two types of materials: hard (3D printing material) and soft (porcine fat) MUTs with 2-mm thickness and 25, 35-mm radius of curvature are choosing to be MUTs in the experiment. According to the measurement results, the proposed method has high accuracy in estimating the properties of the curved MUTs. When the TCSRR is aligned with the center of the curved MUT, the estimated errors of the thickness and radius of curvature of the hard MUTs are 0.12 mm and 2.44 mm, respectively; while the estimated errors of the soft MUTs are 0.18 mm and 1.38 mm, which shows the high accuracy of the proposed method. Also, several discussions on the influence of the misalignment between the center of MUTs and TCSRR that may occur during measurement is presented. When a 3-mm x-axis misalignment occurred, the maximum errors of estimated thickness and radius of curvature of the hard and soft MUTs are 1.85 mm, 36.15 mm, and 1.99 mm, 22.02 mm, respectively. And if a 3-mm y-axis misalignment occurred, the maximum errors are 0.19 mm, 5.14 mm, and 0.22 mm, 7.67 mm, respectively. Regarding the influence of the air gap, the estimated errors of the two MUTs are 0.26 mm, 4.93 mm, and 0.22 mm, 6.94 mm under the 0.1-mm air gap, indicating that TCSR also has a certain tolerance for the air gap effect of the curved MUT. The above measurement results confirm the reliability and accuracy of the proposed method and provide a convenient and stable sensing method for measuring the curved surface MUT with the microwave method.

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