谐振区地海表面上三维运动目标的近、远场电磁散射特性研究

项目名称： 谐振区地海表面上三维运动目标的近、远场电磁散射特性研究

项目编号： No.61201070

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 电子学与信息系统

项目作者： 匡磊

作者单位： 华东师范大学

项目金额： 25万元

中文摘要： 本课题基于FDTD方法对运动目标在地海表面上的复合电磁散射进行预估。首先，结合相对边界条件研究单独运动目标的电磁散射，并提出改进算法。然后，采用周期性延拓面法消除边缘绕射，计算三维大角度入射情形下的粗糙面散射，并根据二次激励法建立运动目标与粗糙下垫面复合模型的电磁散射。利用近远场变换，由计算区域内的电磁场外推出复合模型的远区散射场。接着，为研究粗糙面上运动目标的宽频带散射特性，将调制高斯脉冲波运用于斜入射情形下的周期边界条件，计算复合模型的时域瞬态散射波形，通过傅立叶变换获得宽频带散射。同时用Spectral FDTD方法研究宽频带散射，对比两种方法的数值结果，相互验证。最后，基于球多极展开方法，利用FDTD计算区域内的散射场值求解计算区域外散射场的球多极展开式，外推有限距离处的近场散射分布，与实验测量数据对比验证。本课题的研究为地海面上运动目标的识别及对目标实施隐身措施提供理论依据。

中文关键词： 电磁散射；时域有限差分法；有限元法；洛伦兹变换；雷达散射截面

英文摘要： Composite electromagnetic scattering from a moving object above a land or sea surface is studied by using FDTD (Finite Difference Time Domain) method. Firstly, we calculate the scattering of a single moving object combining the FDTD method with the relativistic boundary conditions. And an improved method is proposed to accelerate computation in this project. Secondly, we take a rough surface as a periodic structure to eliminate its edge effects and calculate a three dimensional model of rough surface with large incident angles. Then we construct a electromagnetic scattering model for a moving object above a rough surface. Scattered fields from a rough surface are computed in the FDTD region. And the scattered fields and incident fields are both introduced to excite the model of a moving object above a rough surface. Scattered fields from a target and a rough surface in the near zone are computed. And omnidirectional scattering from the composite model is computed by near-to-far zone transform. Thirdly, wideband electromagnetic scattering model of a moving target above a rough surface is studied. To implement the wideband computation capability of FDTD, the sin/cos modulation gaussian pulse is applied to periodic boundary conditions. Then scattering from the composite model is computed in time domain. By Fourier

英文关键词： Electromagnetic Scattering；FDTD；FEM；Lorentz Transform；RCS