基于多层平面波分解的快速近远场转换新方法研究

项目名称： 基于多层平面波分解的快速近远场转换新方法研究

项目编号： No.61501298

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 无线电电子学、电信技术

项目作者： 贺新毅

作者单位： 上海无线电设备研究所

项目金额： 19万元

中文摘要： 目标电磁散射特性的近远场转换是通过近场测试获取目标雷达散射截面的关键技术。传统的近远场转换有基于平面波综合和基于目标散射中心两种方法：前者由于巨大的近场双站采样量和计算量，难以扩展至电大尺寸目标的散射问题；后者需要规则面上的宽频带单站采样，但不能解决强耦合目标问题。本项目提出的基于多层平面波分解的快速近远场转换方法，根据加法定理用多层平面波展开目标散射近场，用多层快速多极子算法加速球面波的平面波谱展开过程。这种方法既可用于基于三天线链式关系的双站采样完备散射模型，又可用于基于目标散射中心的单站采样线性散射模型，具有以下优势：使用多层快速多极子算法加速近远场转换过程，降低算法复杂度；测试天线和采样位置引起的影响完全在迭代求逆算法中得到补偿，极具灵活性；采样量与多极子展开阶数一致，达到非余量采样；理论体系完整，误差可控。本项目研究从理论推导入手，开展快速算法数值实现，最后在微波暗室中实测验证。

中文关键词： 目标雷达散射特性；电磁散射计算；近场成像；近远场转换；近场测量

英文摘要： The Near-Field Far-Field Transformations (NFFFT) of target electromagnetic scattering is important in the Radar Cross Section (RCS) measurement in Near-Field. The traditional NFFFT methods include the plane-wave synthesis based methods and the scattering center distribution based methods. The plane-wave synthesis based methods are hard to solve the electrically large targets’ scattering problem because of the enormous measurement efforts and high computational cost. The scattering center distribution based methods work with broadband monostatic observations on sphere or plane or cylindrical surface, the need with the fast measurement scene still inconformity. The scattering center distribution based methods cannot handle the strong coupling effect in target because the high-order scattering component is ignored. The extra antenna pattern compensation is needed in both the two traditional NFFFT methods. In the project we present a fast NFFFT method by multilevel plane-wave decomposition, which is derived from a spherical expansion of the near-field according to addition theorem, and rather accelerate the plane wave modes expanding using multilevel fast multipole method (MLFMM). The fast method can apply to the full model with full bistiatic measurements, and can also apply to the linear model with monostatic measurements. There are many advantages of the fast method: the MLFMM acceleration reduces the computational cast; the great flexibility with respect to measurement locations and probes, because such effects are fully compensated in the iterative inversion algorithm; the sampling number is the same as the multipole order, it’s a nonredundant sampling scheme on arbitrary surfaces; the self-contained theory system make it easy to control and analysis the error. In the project, the theoretical derivation will do firstly. Second, we will numerically implement the MLFMM-based NFFFT method. At last, the experiments will be performed in the chamber.

英文关键词： Target Radar Scattering Characteristic;Electromagnetic Scattering Calculation;Near-Field Imaging;Near-Field Far-Field Transformations;Near-Field Measurement