此篇論文致力於研究低損耗之兆赫元件，我們先藉由設計並製造0.4 THz和1 THz的模式轉換器。在設計上我們有良好的表現，兩個模式轉換器的純度都在90%以上，並且有著相當寬的頻帶(380-420 GHz, 中心頻為400 GHz的TE41模式轉換器以及 910-980 GHz, 中心頻為1THz的TE01模式轉換器)。而傳統加工達不到此元件的加工需求，我們嘗試著使用x-ray LIGA這種精密的微製程加工技術來製作我們的元件。深寬比可以高過5，並且最小線寬可以達到奈米等級，成功的製作出元件。接著我們繼續研究布拉格結構下低損耗的平行板波導管，我們使用布拉格結構來組成我們的平行板，在設計中布拉格平行板波導管(BPPWG)的衰減常數(0.02757 dB/m)遠比傳統的金屬板波導管(MPPWG)的衰減常數(2.76428 dB/m)低上許多，而兩者的行為模式則是相仿。這代表著我們使用BPPWG來取代MPPWG時，能得到更低的損耗。

In this report, two mode converters are designed and fabricated to extract TE41 and TE01 modes for the generations of 0.4 THz and 1 THz signal by high-harmonic interaction with gyrating electron beam, respectively. The purities of the desired modes in these two converters are both higher than 90% with remarkably broad bandwidth (380 GHz to 420 GHz for TE41 mode and 910GHz to 995 GHz for TE01 mode). We therefore employed X-ray lithography to fabricate these designs, which will be characterized by THz time-domain spectroscopy. We also employs the idea of distributed Bragg reflector (DBR), which is a periodic structure formed from alternating dielectric layers. The Bragg reflector can be used to achieve nearly total reflection within a range of frequencies. Instead of the metallic parallel plate waveguide (MPPWG), we propose the Bragg parallel plate waveguide (BPPWG). The BPPWG is a very low loss waveguide as compared with the MPPWG which has a serious conducting loss at the terahertz region. The attenuation constant of our low loss BPPWG (0.02757 dB/m) for the lowest order transverse electric wave mode is two-order lower than that of MPPWG (2.76428 dB/m) at 1THz. And the cutoff frequency, the dispersion relation, and the propagating constant of BPPWG are similar to those of MPPWG. Therefore, we can replace the metallic sidewall with Bragg structured sidewall for many applications

目錄
摘要…………………………………………………………………………1
Abstract……………………………………………………………………...2
致謝……………………………………………………………………….…3
目錄………………………………………………………………………….4
第一章 序論………………………………………………………………...6
1.1簡介………………………………………………………………...6
1.2兆赫波應用………………………………………………………...6
1.3 研究動機…………………………………………………………..8
第二章 兆赫模式轉換器…………………………………………………...9
2.1模式轉換器工作原理介紹………………………………………...9
2.2模式轉換器之特性……………………………………………….11
2.3模式轉換器設計以及模擬……………………………………….14
第三章 微製程技術……………………………………………………….21
3.1製程方法選擇…………………………………………………….21
3.2 LIGA製程技術…………………………………………………..22
3.3 LIGA製程技術流程……………………………………………..29
3.4 DRIE製程技術…………………………………………………..36
3.5 實驗結果比較…………………………………………………...41
第四章 布拉格平行板波導管……………………………………………46
4.1布拉格結構………………………………………………………46
4.2布洛赫波…………………………………………………………49
4.3布拉格平行板波導管理論模型…………………………………51
4.4理論模擬計算以及分析…………………………………………57
4.5實驗架設及量測結果……………………………………………64
第五章 總結及未來展望…………………………………………………68
參考文獻…………………………………………………………………..69

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