開口式共振腔之時域與能流分析

Time Domain and Power Flow Analysis of Open Cavity

李國豪(Guo-Hao Li)

指導教授 ： 朱國瑞

國立臺灣大學/理學院/物理學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201901658

摘要

開口式共振腔常用於磁控管中，因非完全封閉的邊界，所以其特徵與封閉式共振腔相差甚遠。本文運用程式模擬做數值分析，做更深入了解該共振腔的物理特性。
從時域模型出發，推導該模型的數學基礎和所使用邊界條件，且定義時域分析下的品質因子，以及探討不同物理外觀下品質因子和共振頻率的交互關係。
後半則是站在能量流動的角度下，重新看開口式共振腔的行為，改變共振腔的物理結構，看能量流動和耗散行為，細看行進波、反向波功率對品質因子的影響，並由電動力學所得之結果，運用程式予以驗證，並解釋該特徵。

關鍵字

開口式共振腔 ； 品質因子 ； 共振頻率 ； 時域法 ； 能量流

並列摘要

Open cavities are commonly used in research of gyrotrons. Because not closed geometrical boundary, the features that is basically different from close cavity. Hence, we use numerical simulation to understand its physical peoperty and phenomenon.
Start from time domain models and declare the numerical algorithm and the boundary condition. We want to find the relation of quality factor and resonant frequency in time domain models in different structure.
We also discuss the power flow in open cavities . By changing the structure of open cavities , we analyze the flow and decay of energies and forward power、backward power. We derive the formula of power flow by electrodynamics and check our guess by numerical simulation. Finally we try to give an appropriate physical explanation for the results.

並列關鍵字

Open Cavities ； resonant frequency ； quality factor ； time domain ； power flow

參考文獻

[1] K. R. Chu, “Time Domain Analysis of Open Cavity’, Tsing Hua University. Taiwan, R.O.C. (1993)

[2] J. D. Jackson, “Classical Electrodynamics”, John Wiley & son, Inc., p.p. 353-374 (1998)

[3] Y. J. Huang, L. H. Yeh, and K. R. Chu, “An analytical study on the diffraction quality factor of open cavities”, Physics of Plasmas 21, 103112 (2014)

Doi: 10.1063/1.4900415

[4] 王俊霖, “開口式共振腔之能流分析”, 國立臺灣大學碩士論文, (2018)