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Title: | 特高頻壓電超晶格極子天線之電磁輻射分析 EM Radiation Analysis of Piezoelectric Superlattice Polariton-Based UHF Antenna |
Authors: | Shang-Hsuan Li 李尚軒 |
Advisor: | 劉建豪(Chien-Hao Liu) |
Co-Advisor: | 周元昉(Yuan-Fang Chou) |
Keyword: | 壓電超晶格,極子,天線微型化,阻抗匹配,場型, piezoelectric superlattice,antenna miniaturization,impedance matching,radiation pattern, |
Publication Year : | 2018 |
Degree: | 碩士 |
Abstract: | 低頻天線常用在軍事、航海、救援探勘等領域的通訊,因為長距離能量損失少,但是其尺寸過大造成使用不便,使得對於小天線的需求日益增加。有鑑於此,本研究基於壓電超晶格極子理論的週期結構,目的為製作出微型化的UHF 頻段壓電超晶格極子天線。
本研究提出的壓電超晶格極子天線尺寸為 ka< 0.15,原理為利用電磁波與機械波耦合的極子特性在346.2 ~ 346.7 MHz 頻段激發與接收電磁波,達成天線微型化。因此本研究提出選用500 μm 厚的鐵電材料鈮酸鋰,將表面施以高電壓製作19 μm 的週期週期極化鈮酸鋰製作壓電超晶格,並依據鈮酸鋰的反轉特性PSpice 模擬軟體作為輔助,以3.3 秒成功極化。 本研究發現於遠場輻射量測證明本天線在344.5 MHz 對應Ω=1 主要為極子波有更多的能量轉為機械能,經過共振與反共振點頻率後在346.2 ~ 346.7 MHz處的Ω=1.005 為真正的輻射頻段,壓電超晶格天線於此輻射頻段比未極化之鈮酸鋰具有著2.5 dB 的輻射提升。除此之外,場型量測中得到本天線的輻射場型,更加入微帶線進行阻抗匹配增加接收功率,也能進一步確認本天線的場型形式,同時驗證分析在輻射頻段內的接收能力依序為週期極化鈮酸鋰、鈮酸鋰、銅箔膠帶,顯示本壓電超晶格極子天線具備電磁能力。 In the last century, low frequency antennas have been flourishing in the domain of military, marine, rescuing and exploration, but the use of those antennas has been limited by their gigantic sizes. The large sizes result in an increasing demand for small antennas. In view of the issue, a UHF band piezoelectric superlattice polariton-based antenna has been proposed in order to accomplish the antenna miniaturization. A 500 μm thick, period of 19 μm ferroelectric lithium niobate is periodically poled in 3.3 seconds with the aid of its inversion characteristics and PSpice simulation. The size of the proposed piezoelectric superlattice polariton-based antenna is designed as ka<0.15. The electromagnetic characteristics of the electromagnetic wave and the mechanical wave coupled in the piezoelectric superlattice are used to excite and receive electromagnetic waves for the proposed miniaturized antenna to operate from 346.2 to 346.7 MHz. According to the far field radiation measurement, the antenna converts more energy into mechanical energy at 344.5 MHz (Ω=1) and radiates at 346.2 ~ 346.7 MHz(Ω=1.005) where has 2.5 dB radiation boost compared to lithium niobate. The type of radiation pattern is also obtained. Furthermore, the transmission line impedance matching network not only improves the received power, but also confirms the the antenna type. The receiving capability in descending order are piezoelectric superlattice polariton-based antenna, lithium niobate and copper foil tape, showing that the proposed antenna has radiation capability. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/78867 |
DOI: | 10.6342/NTU201804399 |
Fulltext Rights: | 有償授權 |
metadata.dc.date.embargo-lift: | 2023-12-28 |
Appears in Collections: | 機械工程學系 |
Files in This Item:
File | Size | Format | |
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ntu-107-R05522519-1.pdf Restricted Access | 11.42 MB | Adobe PDF |
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