- 學位論文
週期極化鈮酸鋰之電磁波輻射與接收研究
PPLN Electromagnetic Wave Radiation and Reception Research
摘要
1888年赫茲(Heinrich Hertz)以偶極天線實驗證明了馬克斯威爾(James Clerk Maxwell)電磁波理論的真實性。自此天線的發明，人類對電磁波的運用有了跨時代的進步。天線的基本原理，是將實體電路中的電流信號轉變為特定頻率的電磁波信號，以指定的方位輻射出去。另一端，相同的物理原理，將接收此電磁波信號轉換為電流信號以供實體電路使用，於是實體電路系統中的訊息便可於無線鏈路中互相傳遞，其間無需任何介質，簡而言之，天線是為電磁波資訊傳遞的收發媒介裝置。 天線種類於今各式各樣，但以週期性調變的壓電材料來做為電磁波信號的發收天線，至今無人嘗試，本篇撰寫之目的，希望能擺脫過往天線的傳統型態，而以週期極化鈮酸鋰之壓電超晶格來取代以往天線的功能。 週期極化鈮酸鋰(Periodically Poled Lithium Niobate)晶體具有接收與幅射電磁波物理性質，內部的波傳行為兼具電磁波與機械波，此類調變晶體特稱為壓電超晶格。利用此晶體內極子的波傳特性，於13.56MHz的頻率激發內部極子震盪，表現出來的電磁波收發現象，是作為此新式天線的主要關鍵理論。 本篇以RFID(Radio Frequency Identification)無線射頻辨識系統來做為實驗測試的基本架構，系統中移動式標籤是為資料的攜帶者，主機藉經由ID Controller解碼後，利用讀寫器發射電磁波信號，與標籤進行相互資料交流。標籤中，為感應讀寫器的電磁波，一般而言需設置金屬線圈以做為天線之用，本篇研製週期性調變的鈮酸鋰晶圓，可於13.56MHz特定頻率來引發其對應週期的PPLN內部極子震盪，並對此週期調變晶圓其接收與幅射電磁波的物理性質有一系列的完整探討，希望藉此研製出嶄新不同的電磁波收發裝置。
並列摘要
In the year of 1888, Heinrich Hertz conducted the dipole antenna experiment to prove the authenticity of the electromagnetic wave theory of Maxwell (James Clerk Maxwell). Since the invention of the antenna, the application of electromagnetic waves ushers a new era. The basic principle of the antenna that it transforms the circuit current signal into a specific frequency of electromagnetic signals and then radiates the wave by specific orientation. On the other end, after receiving the electromagnetic signal, by the same physical principle, antenna transforms the wave into the current signal for circuit system use. So that messages of independent circuit systems can be transmitted by way of wireless link to each other, without any medium en route. In a nutshell, the antenna is a media device for transmission and reception of electromagnetic waves. There are various types of antenna today, but, so far ,no one has ever applied periodic modulation of piezoelectric materials as an antenna to send and receive electromagnetic signals. Purpose of this dissertation is to get rid of the tradition of the antenna pattern, but to use periodically poled lithium niobate to replace the conventional one. Periodically poled lithium niobate (PPLN) crystal has physical properties to receive and radiate electromagnetic waves. It has both types of propagation behavior of electromagnetic and mechanical waves. Such modulation crystal is also known as piezoelectric superlattices (PSLs). With this crystal wave propagation characteristics， EM wave reception and radiation phenomenon caused by polariton excitation at 13.56MHz frequency is the key of this new antenna theory. This experiment takes RFID (Radio Frequency Identification) systems as basic structure for test. Tag, one part of the RFID system, is portable data carrier. After decoding by ID Controller, Reader transmits electromagnetic signals and exchanges information with Tag. In general , to induct the electromagnetic wave from Reader , it needs to set up metal coils in Tag as antenna. The thesis develops periodic modulation lithium niobate chip, in which polariton excites at 13.56MHz frequency in behavior of mechanical and electromagnetic wave, and has series of full measurement on the chip physical properties, hoping to invent a new type of electromagnetic wave transceiver.