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標題: | 機械式可調變頻率選擇表面之大範圍應用 Mechanically Tunable Frequency Selective Surfaces for Large-Scale Application |
作者: | Yu-Chieh Hung 洪鈺傑 |
指導教授: | 劉建豪(Chien-Hao Liu) |
關鍵字: | 頻率選擇表面,可調式濾波器,連桿機構,軟性基板,週期結構, Large-Area Planar Frequency Selective Surfaces,Periodical Structure,Tunable Filter,Linkage Mechanism,Stretchable Substrate,Ultra-Wideband Tuning, |
出版年 : | 2017 |
學位: | 碩士 |
摘要: | 頻率選擇表面由Ben A. Munk 有系統地整理提出,利用每一個單元(Unit cell)在空間中週期性排列,組成一種特殊的屏障,透由此表面可對入射的電磁波產生不同的物理特性改變,可吸收或反射特定頻段,近年研究方向將頻率選擇表面設計為可調節式,利用不同的調節方式改變其頻率範圍,便不需要重新設計和製作。
目前常見調節方式包含電子式、流體式、磁性材料、記憶合金、電漿等,但是這些調節方式有各自的優缺點,根據現有研究調查,目前的調頻技術有兩大困難之處需要突破。第一困難之處是通常頻率選擇表面放置環境較險峻的位置,例如高建築物的牆壁上或大型雷達站的外圍,如何使用穩定的調節方式就變成需要突破的挑戰;第二困難之處是對頻率選擇表面作大面積的調節,隨著面積增加,需要控制單位數量的致動器或驅動電路跟著增加,要如何同步(synchronously) 驅動致動器成為一個重要的課題。 本研究的目的為解決與改進上述調節頻率選擇表面的兩個困難之處,並且增加頻率選擇表面的應用層面。主要分為三種調節方式探討:1.拉伸式金屬導線2.可旋轉式金屬導體陣列3.連動桿金屬導體陣列,上列的調節方式有效解決現有的問題,亦不受限於環境限制,特別是在同步驅動每一個單元時,本研究提出的方法較其他現有的相關研究團隊提出的方法更容易達成,不論任何面積大小,不同尺寸的空間濾波器亦可以以相同方式製作,且不需任何主動元件即可達到效果,這一類的機構也可用在不同用途的陣列式結構,因此本研究所提出的實作成果與模擬結果比較的內容,將在各章節進行討論。 The frequency selective surface theory is systematically collated by Ben A. Munk,which is using each unit cell periodically arranged in space to form a special barrier. When the incident electromagnetic waves transmit through the structure, which can convert the physical characteristics of electromagnetic field by absorbing or reflecting the specific frequency band. In recent years, the research direction of the frequency selective surface is focus on tunable device. It is effective for different adjustment methods to change its frequency range so as not to need to re-design and production. At present, the common tuning methods include by electronic elements, metal fluid, magnetic materials, memory alloy, plasma space, etc., but these methods have their own advantages and disadvantages, according to the existing research survey, the current tuning techniques have two major difficulties to overcome. The first difficulty is that the environment applied frequency selective the surface is sually at severe location, such as high-building walls or large radar stations on the periphery. How to use a stable tunable method becomes a tall order. The second difficulty is to actuate the frequency selective surface in large area dimension. As the area increases, it is necessary to increase the number of actuators or drive circuits, and how to synchronize the actuator to become an important topic. The purpose of this study is to address two difficulties in improving the abovementioned tunable frequency selective surface and to increase the application level. This study is divided into three types of tuning methods with econfigurable structure: 1.Stretchable metal geometry on flexible substrate 2. Control conductor array by rotatable mechanism 3. Conductor array transformed by linkage mechanism. Above of all adjustment method can effectively solve the existing problems, and no limitation with environment setting. These methods proposed in this study is easier to achieve than other existing design from other research teams, and the different sizes of spatial filters can be made in the same way without additional fabrication steps. Moreover, these mechanism tuning can also be used in other application of the array structure. The sum of this study and simulation results will be discussed in each chapters. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/68317 |
DOI: | 10.6342/NTU201703113 |
全文授權: | 有償授權 |
顯示於系所單位: | 機械工程學系 |
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