# 臺灣博碩士論文加值系統

(44.192.92.49) 您好！臺灣時間：2023/06/08 06:50

:::

### 詳目顯示

:

• 被引用:0
• 點閱:235
• 評分:
• 下載:0
• 書目收藏:0
 本論文研究多層各向異性物體之逆散射。當一個TE或TM波照射在一 個未知介電分佈 的物體，吾人可測得外部的散射場，經由對此散射場做 適當的處理，可以得知此物體的介電分佈情形。我們將考慮一個具有任意 截面形狀的柱體，該物體可以是單層或多層且為各向異性的結構，而其介 電分佈則可為均勻或不均勻。 我們使用無關聯照射法來解此逆散射問題。理論方面，此種散射問題可使 用等效電 流的觀念來分析。經由適當的邊界條件，吾人可導出一組非線 性積分方程式，然後使用動差法和無關聯照射法來解之，可分別得到正散 射和逆散射的公式。數值模擬方面，可用正散射公式模擬已知介電分佈物 體的散射場，再將此散射場代回逆散射公式，便可得到此柱體介電分佈的 重建結果。 由於各向異性介質物體的介電參數會隨所選的座標系統而變，所以先前的 研究皆要 求事先知道其主軸方向。本論文的特點是探討如何在主軸未知 的情況下，找出重建物體介電(張量)分佈的逆散射法則。且更進一步用在 多層及/或不均勻的柱體。 數值模擬方面，吾人先 對模擬散射場法則進行驗證，可得到和理論值誤差極小的結 果。再針對 截面形狀為長方形、正方形和圓形的柱體及各種多層結構進行重建的工作 ，其結果也相當令人滿意。此外，也將探討不同數目的外圍量測點與散射 場雜訊對此法則的影響。
 In this thesis the inverse scattering of a multi-layered anisotropic cylinder is investigated. Assume that a TE and/ or TM wave is incident upon objects of unknown dielectric distribution and the scattered fields are measured outside. By properly processing the scattered field, the dielectric distribution of the objects can be reconstructed. A cylindrical object with arbitrary cross-section shape is considered, which may consist of single layer or multi- layered anisotropic material with homogeneous and inhomogeneousdistribution. We use unrelated illumination method to solve this inverse scattering problem, theoretically, the scattered problems can be analyzed using the concept of equivalent current. By applying appropriate boundary conditions, a set of nonlinear integral equations can be derived. The forward scattering formula and inverse scattering formula are derived by the use of moment methodand unrelated illumination method, respectively, based on a set of integral equations mentioned above. For numerical simulation, the scattered fields from a known object are generated by the forward scattering formula, then the scattered field data are plugged into the inverse scattering formula, from which the dielectric distribution of the object can be reconstructed. The dielectric parameters of anisotropic materials depend on the specified coordinate system, so previous researches all require the knowledge of the principal axes of the measured object in advance. But the purpose of this research is to develop the inverse algorithm for reconstructing the distribution of the material permittivity (a tensor) of the measured object, of which the principal axes are assumed unknown in general, and, furthermore, apply this on a multi-layered and/or inhomogeneous cylinders. Satisfactory reconstruction had been obtained from this inverse algorithm. We'll present various kinds of inhomogeneous and multi-layered anisotropic cylinder with different cross- sections, which include rectangular, square and circular shape. In addition, the effects of the number of external measured points and the noise level upon the scheme are also investigated.
 國圖紙本論文
 推文當script無法執行時可按︰推文 網路書籤當script無法執行時可按︰網路書籤 推薦當script無法執行時可按︰推薦 評分當script無法執行時可按︰評分 引用網址當script無法執行時可按︰引用網址 轉寄當script無法執行時可按︰轉寄

 1 三層介質中掩埋雙軸性複雜物體之電磁成像 2 二維物體之電磁逆散射 3 不均介質物體之逆散射

 無相關期刊

 1 雙節式阻抗轉換支線混波器之設計及其最佳頻寬之分析 2 雙節式阻抗轉換支線混波器之設計及其最佳頻寬之分析 3 方形環狀及H型槽孔天線特性之研究 4 微帶環形槽孔天線的分析與設計 5 矽製程射頻積體電路多層螺旋電感 6 以Cubic-spline及遺傳演算法重建二維柱體微波影像 7 應用遺傳演算法於天線陣列之最佳化 8 應用改良運算子增進遺傳演算法效率之研究 9 遺傳演算法在二維柱體微波影像的應用 10 利用遺傳演算法則最佳化弧形陣列天線場型 11 利用遺傳演算法則對多節式阻抗換支線混成器之最佳化設計與分析 12 具降雨量預測之智慧農業灌溉系統 13 平行板電容的線性度強化結構的探討 14 符合IEEE802.16e-2005標準的移動式WiMAX多頻帶(2.4-6GHz)小型天線的設計 15 多層彎繞縮小化超寬頻單極天線設計

 簡易查詢 | 進階查詢 | 熱門排行 | 我的研究室