現代化的生活，許多設備越來越精密、敏感，使得電磁干擾的問題逐漸被人重視，設計者對於模擬的需求也相對提高，常需要考慮多種情況的複雜問題，但是頻域演算法的運算時間隨問題的複雜度呈曲線成長，而時域演算法則呈線性成長，在高度複雜問題情況時，時域演算法效率將會大過頻域的演算法，像是飛彈的電磁干擾就相當適合使用時域的演算法來求解。
FDTD次網格法可以使用不同精度的網格描述整體計算空間區域內的結構，提升演算法的模擬效率，故次網格法的穩定性及準確度為各方研究的熱門課題。
本文提出適應性調整時間步階結合非均勻網格法來做為主次網格邊界面上的連結機制，以達到一次性的連結面處理來增加穩定度，且不需調降時間步階可提升運算速度。
最後使用上述提出的方法模擬一個飛彈近似模型的電磁干擾效應，將印刷電路板以次網格描述，其餘結構則以主網格描述，主次網格採用1:5的比例建置，以一個高斯平面波不同角度打向飛彈模型，模擬電磁脈衝對飛彈內印刷電路板的影響，與FEM演算法軟體HFSS比較，說明我們方法的可行性。

Electromagnetic interference problems have become serious gradually because many devices are getting more sophisticated and sensitive in modern life. Designers often need to consider a variety of situations complex problems so their demand for software also enhanced. Computation time of the frequency domain algorithm grows with the complexity of the problem, but the time domain algorithm is linear growth. Therefore, the efficiency of time domain algorithm will be greater than the frequency domain algorithm at highly complex issue. It’s quite suitable to analyze electromagnetic interference of missiles using time domain algorithm.
Subgridding FDTD method can enhance the efficiency of simulation by using different precision grid to describe any structure in the whole computational domain. Therefore, the stability and accuracy of the subgrid method are both popular topics for studies around the world. In this thesis, we proposed the adaptive time step method combined with non-uniform grid method to link boundary between main grid and local grid. One-time’s surface coupling process doesn’t need to lower time step, therefore, the stability and the computing speed can be improved effectively.
In the second part, we analyze electromagnetic interference of missile’s model using the method described above. The PCB structure is built by local grid, the remaining structures are built by main grid, two types of grid are defined by a scale of one to five. To simulate electromagnetic pulse, a Gaussian plane wave was passed through the missile model in different angle. To explain the feasibility of our approach, the result will be compared with HFSS at last.

目錄
論文審定書.................................................................................................i
誌謝............................................................................................................ii
中文摘要...................................................................................................iii
英文摘要...................................................................................................iv
目錄............................................................................................................v
圖表目錄...................................................................................................viii
第一章 序論 1
1.1研究目的與方法 1
1.2 論文大綱 3
第二章 FDTD演算法 5
2.1 FDTD介紹 5
2.1.1 FDTD公式推導 5
2.1.2 Courant 穩定準則 8
2.1.3 吸收邊界 8
2.2 集總電路元件的模擬 10
2.2.1 電阻 10
2.2.2 阻抗性電壓源 11
2.2.3 電容 12
2.2.4 電感 12
2.2.5 二極體 12
2.3 FDTD模擬 13
第三章 保形時域有限差分法及非均勻網格法 15
3.1 Conformal FDTD 介紹 15
3.2 Conformal FDTD 公式推導 15
3.3 非均勻網格法介紹 21
3.4 非均勻網格法推導 22
3.5 非均勻Yee網格的誤差評估 25
第四章 次網格法 27
4.1 傳統次網格法介紹 27
4.1.1 傳統次網格演算法 27
4.1.2 數值不穩定現象 28
4.2 適應性調整時間步階程序介紹 31
4.3 FDTD次網格法 34
4.4 次網格法模擬驗證 38
4.5 使用非均勻網格之次網格法 42
第五章 飛彈模型之電磁干擾模擬 46
5.1 介紹 46
5.2 印刷電路板的耦合機制 47
5.3 電磁波對印刷電路板的干擾 49
5.4 斜向入射平面波之電磁干擾與圓柱飛彈模型模擬 52
5.5 模擬圖形ripple狀的改善 56
第六章 結論 60

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