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Title: | 開口式共振腔之衍射品質因子之解析研究 An Analytical Study on the Diffraction Quality Factor of an Open Cavity |
Authors: | Yu-Jie Huang 黃榆傑 |
Advisor: | 朱國瑞 |
Keyword: | 開口式共振腔,磁旋管,品質因子,縮尺法則,黎卡提方程, open cavities,gyrotrons,quality factor,scaling law,Riccati equation, |
Publication Year : | 2014 |
Degree: | 碩士 |
Abstract: | 開口式共振腔是磁旋管的作用結構,它為毫米、次毫米和太赫兹波段,提供了新的同調電磁波源。共振腔的一個開口端,是用來快速提取由高能電子束所產生的輻射能,在大多數的情況下,來自開口端的衍射損耗遠大於管壁的歐姆損耗,並且導致了低品質因子Q。在較早的研究中,對於微變截面的波導已求出了衍射Q 的解析公式,不過在這裡,另一個適用於更一般波導的公式被求出。在低階軸向模態的最低階近似下,它可化簡成先前的結果。至於較高階的軸向模態,它給出了更精準的Q,且由數個不同橫向模態的數值結果所驗證。 Open cavities are the interaction structures for a new generation of coherent millimeter, sub-millimeter, and terahertz radiation sources called the gyrotron. One of the open ends of the cavity is intended for rapid extraction of the radiation generated by a powerful electron beam. In the majority of cases, the diffraction loss from this open end dominates over the Ohmic losses on the walls and it results in a low quality factor Q. In earlier studies, an analytical expression of the diffraction Q was derived for weakly irregular waveguide. However, here another expression valid for a more general waveguide is derived. It reduces to previous one in the lowest order expansion of low-order axial mode. And for higher-order axial mode, it gives more precise Q, verified by numerical examples for various transverse modes. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/56235 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 物理學系 |
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