- 學位論文
使用LIGA製做1THz TE01模式轉換元件
Using LIGA process to fabricate 1THz TE01 mode convert
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摘要
本篇論文主要為設計與製作THz頻段的TE01模式轉換器元件，建立一套高效率、高精度的X光深刻技術，實際應用於深度0.238mm的1THz TE01模式轉換器，此元件主要可以應用於提供長距離傳輸的低損耗波導一個純度高的TE01波源。 在元件設計的部分使用到高頻結構模擬軟體(Ansoft HFSS 13.0)，由於TE01模式在圓波導中屬於高次模較難以激發，因此在結構的部分使用Y型分波器分出四道等相位等大小的波注入圓形波導，耦合出圓極化的TE01模式。藉由優化分波器的結構使模式轉換器有較高的穿透效率與頻寬。 而製造部分，實驗室之前選用SU-8這支光阻進行微機械加工(LIGA)方式製作400GHz的TE41模式轉換元件，但在最後一步光阻去除的過程中，由於SU-8難以除去，使得去除效果並不是很好，此結果會反應在元件的穿透效率和模式的耦合度。因此這次製造我們試著使用一支新的光阻KMPR，此光阻的特性與SU-8相似，但是容易除去，希望能使用這支光阻建立一套省時、省錢、效果佳的製程。 另外，鑒於實驗室的網路分析儀(Network Analyzer)所支援的頻帶最高只能達到110GHz，所以我們結合光學上的TDS(Time Domain Spectrum)量測系統來測量元件，藉由將高斯波包型式的THz pulse聚焦進元件內，再經過一些數學計算間接得知穿透效率，使我們能夠獲得此元件在兆赫波段的穿透對頻率之響應。
並列摘要
The thesis containing design and fabricate the TE01 mode convert at THz band to establish a high-efficiency and high-precision X-ray lightgrophy technique. The technique is application to fabricate TE01 mode convert of 0.238mm thickness at THz band, and this mode convert can be used to provide a purity TE01 source for a low-loss cylinder waveguide. At design part, we use high-frequency structure simulation(Ansoft HFSS 13.0) to design our element. Due to TE01 mode is high order mode in cylindrical waveguide, so we using side wall coupling way (Y-type structure) to excite it. As the injected THz wave (TE10) travels to the first power-dividing junction, it would be split into two signals with equal amplitudes and phases. These two signals keep propagating forward and will be subsequently divided into four sub-signals by the additional two power dividers (Y-shaped). The four arms of the second-stage power dividers finally attach on the side wall of cylindrical waveguide with the symmetric spatial orientations. When the foul equal-amplitude and equal-phase TE10 waves are led into this mode-converting section, their linearly-polarized electric fields circumnavigate the cylindrical waveguide and hence jointly excite the TE01. Finally, the very high-purity circular TE01 mode will emerges at the output end. At fabricate part, we use LIGA process to fabricate the mode convert, and we select KMPR as our photoresist because it can be removed easier than SU-8 by chemical method.
參考文獻
[3] 謝睿哲，"使用LIGA和DRIE製程技術製作400GHz TE41模式轉換元件與量測"，國立清華大學物理所碩士論文，2012。
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