双负媒质论文：双负媒质的宽频散射分析.doc

双负媒质论文：双负媒质的宽频散射分析【中文摘要】双负媒质(DNG)是介电常数和磁导率均为负数的人工复合材料,也称为左手材料。双负媒质具有很多奇异的特性,如光的负折射率,反多普勒效应,反切仑科夫辐射等,在电磁学,光学和材料领域有着巨大的应用前景,其电磁散射特性的分析已成为当前研究的热点之一。首先,该文介绍了双负媒质的研究意义和双负媒质的电磁传输特性,介绍矩量法的基本概念及其相关知识。分别以导体和介质体为例验证了渐近波形估计技术和作为宽频快速算法的有效性。结果表明AWE完全能逼近MOM精确计算结果,同时可加快计算速度。其次,利用渐近波形估计(AWE)技术来研究双负媒质(DNG)的电磁散射特性。文章首先从双负媒质(DNG)的本构关系出发,推导出DNG的PMCHWT方程,从而解出单频率入射波下的电流和雷达散射截面(RCS)；通过对阻抗矩阵元素的处理,实现了阻抗元素高阶导数的求解,成功的将AWE技术应用于DNG宽频电磁计算领域。计算实例表明：AWE计算的结果能很好的逼近精确解,同时大大提高了计算效率。最后,鉴于利用AWE计算双负媒质的宽频响应时高阶导数的求解非常繁琐；文章最后提出利用模型参数估计技术来优化双负媒质宽频快速计算。由于模型参数估计技术在求解相同的矩阵方程时,矩阵求导节数可以降低,因此模型参数估计技术在计算双负媒质的宽频响应时更有优越性。计算实例表明：MBPE计算结果与矩量法逐点计算和AWE计算的结果进行了比较,验证了算法的有效性。【英文摘要】The double-negative (DNG) meta-material is a kind of artificial composite material, in which both the dielectric permittivity and dielectric permeability are negative. This material is also called left-handed material. DNG meta-material has a lot of strange features, such as negative index of refraction material, backwards-wave meta-materials etc. It has potential application in fields of electromagnetics, optics, and materials. Therefore, accurately analyzing the electromagnetic characters in the DNG meta-material is more and more important.Firstly, the paper introduces the significance of DNG meta-material and the electromagnetic transmission characteristics of it. The basic concepts and related knowledge of method of moments (MOM) is introduced. The asymptotic waveform evaluation (AWE), as a frequency-sweep analysis method, is applied to perfectly electrical conducting (PEC) objects and dielectric objects. The results obtained by AWE agree well with that of exact solution or direct MOM, and the computational efficiency is improved significantly by AWE.Secondly, the asymptotic waveform evaluation (AWE) technique is applied to electromagnetic scattering analysis of double-negative (DNG) meta-material. The PMCHWT equation of the DNG meta-material is deduced based on its constitutive relationship. And the surface currents and radar cross section (RCS) at a single frequency point is computed. The impedance matrix elements are processed to achieve high-order derivation computation. Then the AWE technique is applied to obtain broadband RCS frequency response of the DNG. meta-material. A good agreement can be seen between AWE and the exact solution. And the computational efficiency is improved significantly.Finally, in order to reduce the computation complexity of high-order derivation computation in AWE, model-based parameter estimation (MBPE) techniques is introduced. Since for the same matrix equation, the order of derivation for impedance matrix elements can be reduced, the MBPE has more advantages in the frequency-sweep analysis of double negative meta-material. The results of MBPE is also compared with that of exact solution, direct MOM and AWE, and the computational efficiency is improved significantly.【关键词】双负媒质 Drude模型 渐进波形估计 模型参数估计技术 雷达散射截面【英文关键词】Double-Negative meta-material Drude model Asymptotic Waveform Evaluation Model Based Parameter Estimation RCS【目录】双负媒质的宽频散射分析摘要3-4Abstract4-5目录6-8第一章 绪论8-111.1 双负媒质研究背景与意义81.2 雷达及雷达散射截面8-101.3 论文章节安排10-11第二章 基本理论介绍11-242.1 双负媒质的电磁特性知识11-142.2 矩量法的理论介绍14-162.3 PMCHWT方程理论介绍16-182.4 宽频散射的意义18-192.5 AWE技术基本理论介绍19-24第三章:导体宽频散射分析24-333.1 二维理想导体矩量法理论推导24-263.2 二维理想导体宽带RCS的矩量法解26-283.3 利用AWE技术来求解二维理想导体目标宽带RCS28-303.4 二维导体宽频计算实例与分析30-323.5 二维导体计算实例结果分析32-33第四章 介质体宽频散射分析33-394.1 二维介质电磁散射理论推导33-364.2 二维介质体计算实例36-384.3 二维介质体计算实例结果分析38-39第五章:AWE在双负媒质宽频散射分析中应用39-505.1 双负媒质的前期研究39-405.2 双负媒质的PMCHWT方程40-425.3 双负媒质AWE技术的理论推导425.4 维散射