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標題: | 微型化支架天線應用於血管內監測 Miniaturized Stent Antennas for Intravascular Monitoring Applications |
作者: | Shuo-Chih Chen 陳碩志 |
指導教授: | 劉建豪(Chien-Hao Liu) |
關鍵字: | 血管再狹窄化,植入式天線,支架型天線,有限元素法模擬,鈷鉻合金,全向性幅射場型, Vascular Restenosis,Implantable Antenna,Stent Antenna,FEM Simulation,Cobalt-Chromium Alloy,Omnidirectional Radiation Pattern, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 近年來,由於心血管疾病已成為人類主要的死亡原因,因此如何有效治療與防治血管疾病是個相當重要的議題。自從1980年代血管支架的發明後,醫學界利用微創手術讓堵塞血管得以擴張使血流量恢復正常。但由於金屬支架對於血管屬於外來物,因此人體自身修復機制對於支架排斥導致增生一層平滑肌覆蓋於血管內壁。經過長時間後,細胞過度增生而發生血管再狹窄化的情形。因此近年來發展出許多搭配各式感測器整合而成的智慧型支架,將檢測血管再狹窄化的發生與血壓、血糖濃度、血流速度等重要臨床資訊,透過無線通訊的方式傳送到外部監測系統提供即時監控。但由於血管大小的限制,與支架複雜的幾何結構,血管內植入式天線成為重要元件並且需要具備良好的輻射特性。
本研究提出的Single-connector支架型天線,為根據市面上常見的Multi-Link支架組成構造進行優化設計,其方式為每一層Ring結構僅用單個Connector進行連結。且利用ABAQUS對氣球膨脹血管支架的過程中進行有限元素法模擬,藉由觀察支架所受到的最大應力是否超過其材料鈷鉻合金所能承受的最終應力,確保支架型天線符合其機械性質的要求。接著利用CST電磁模擬軟體進行電性分析,觀察到此設計除了可以避免隨機分佈的表面電流,達到不錯的輻射特性以外,同時也能大幅降低其共振頻率,以達到微型化天線的效果。而支架型天線的工作頻率設計在2~3 GHz頻段之間使得電磁波穿越人體器官組織時能有較少的能量損耗。 Single-connector支架型天線利用雷射加工所製成,經由電波無響室進行三維遠場的輻射特性量測,觀察到有近似全向性輻射場型,此結果有利於訊號在全方位進行收發。且在共振頻率2.07 GHz時保持良好的輻射效率74.5 %。本研究藉由此設計提供優化支架型天線的想法,希望能在未來結合IC與各式感測器,使植入式無線通訊與血管內即時監控有更好的發展。 Recently, cardiovascular disease has become the main cause of death in humans. Therefore, how to effectively treat and prevent vascular diseases is a very important issue. Since the invention of the vascular stent in the 1980s, the minimally invasive surgery has been used to solve the vascular obstruction in the medical community. However, since the metal stent is a foreign object to the blood vessel, the proliferation of a layer of smooth muscle covers the inner wall of the blood vessel by the body's own repair mechanism. After a long period of time, this proliferation would lead to the occurrence of vascular restenosis. In recent years, many smart stents have been developed by integrating with various sensors to detect the vascular restenosis and important clinical information such as blood pressure, blood glucose concentration or blood flow velocity. The information then be transmitted to the outside monitoring system through wireless communication. Due to the limited volumes of blood vessels and the complicated geometry of the stent, Implantable antenna with good radiation performance are required for the intravascular application. In this study, we propose the Single-connector stent antenna, which is different from the general Multi-Link stent structure. Each layer of ring in Single-connector stent antenna is connected with only one single connector. The highly biocompatible cobalt-chromium alloy is used for the stent antenna. The FEM simulation method is conducted to observe the distribution of stress and strain on the structure during balloon expansion, and ensure the stent antenna meets the requirements of its mechanical properties by ABAQUS. Then we use CST electromagnetic simulation software for electrical analysis. In addition to avoiding random distribution of surface currents, this design has good radiation characteristics and also reduces its resonant frequency to miniaturize the antenna. The implantable stent antenna is designed at the operating frequency from 2 to 3 GHz to reduce energy loss in the human body and tissues. The single-connector stent antenna is fabricated by laser cutting techniques. The three-dimensional far-field radiation characteristics are measured in the radio wave chamber. We obtain the omnidirectional radiation pattern of the stent antenna. This result is beneficial for the transmission and reception of the signal in arbitrary directions and maintaining a good radiation efficiency of 74.5 % at a resonant frequency of 2.07 GHz. This study provides the optimization of stent antenna with the design. We hope that IC and various sensors will be integrated for the better development of implantable wireless communication and intravascular monitoring in the future. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/21675 |
DOI: | 10.6342/NTU201900997 |
全文授權: | 未授權 |
顯示於系所單位: | 機械工程學系 |
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