复杂电大尺寸各向异性介质涂覆目标电磁特性的快速数值仿真研究

The analysis on the electromagnetic characteristics of complicated electrically large object coated with anisotropic material plays a vital role on the stealth performance improvement, the radar cross section reduction, etc. However, the existing theories and methods cannot meet the increasingly high engineering requirements for the analysis and design of this kind of coated objects. This project aims at achieving the accurate numerical modeling and fast simulations of electrically large object coated with anisotropic material by utilizing modern electromagnetic theory and calculation methods. It first divides the object into the low-frequency region and high-frequency region according to the complexity, while the method of moment (MoM) based on volume-surface integral equation (VSIE) is then employed for the low-frequency region while the modified physical optic (MPO) method for the high-frequency region. Specifically, the project involves the application of the electric flux continuity condition to modify the calculation accuracy of MoM based on VSIE, the modeling of the high frequency region according to the real coated object, and the efficient use of the modern electromagnetic fast algorithm to accelerate the hybrid algorithm which is formed by MoM and MPO. Finally, an efficient fast hybrid algorithm allowing accurate and efficient simulation analysis of the electromagnetic characteristics of electrically large object coated with anisotropic material is developed.

复杂电大尺寸各向异性介质涂覆目标的电磁特性分析在提高目标隐身性能、缩减目标雷达散射截面的设计中起着至关重要的作用，而以现有的理论与方法分析和设计此类涂覆目标已无法满足日益提高的工程需求。本项目旨在利用现代电磁理论和计算方法实现对电大尺寸各向异性介质涂覆目标的精确数值建模与快速高效仿真，首先根据目标各部分结构的复杂程度将目标分为全波法区域与高频法区域，而后采用基于体面积分方程的矩量法计算低频区域，采用修正型物理光学法计算高频区域。主要研究内容包括应用电通量的连续性条件修正基于体面积分方程矩量法的计算精度、依据真实涂覆目标对高频区域进行建模、以及有效利用现代电磁快速算法对结合矩量法与物理光学法形成的混合算法进行加速，最终发展一套有效的快速混合算法，可对电大尺寸各向异性介质涂覆目标的电磁特性进行精确而高效的仿真分析。

复杂电大尺寸双各向异性介质—导体复合目标的电磁特性分析在提高目标隐身性能、缩减目标雷达散射截面（RCS）的设计中起着至关重要的作用，而以现有的理论与方法分析和设计此类目标已无法满足日益提高的工程需求。本项目利用现代电磁理论和计算方法实现了对电大尺寸、任意形状、非均匀双各向异性介质涂覆目标的精确数值建模与快速高效仿真。取得的主要成果为：1.提出了适用于任意形状非均匀双各向异性介质—导体复合目标的体面积分方程（VSIE），利用该方程可实现对任意材料目标电磁特性的求解。通过引入新型基函数、采用提取法来严格处理奇异点等技术保证了计算精度；2.在介质—导体分解面处应用电通量连续性条件以减少体未知量数目并提高求解精度，并详细讨论了连续性条件的适用情况。利用连续性条件改进后的VSIE特别适合求解包含薄涂层的目标；3.结合了基于VSIE的低频全波法和基于大面元物理光学（LEPO）的高频近似法形成高低频混合算法，并采用基于球谐函数展开的多层快速多极子算法（SE-MLFMA）对其进行加速，克服了混合算法计算效率低下、精度低的难题，非常适用于复杂平台上的大型阵列天线电磁分析、考虑包括平台效应的天线阵列设计以及天线优化布局等问题。项目的研究过程中，对多个具有实际工程背景的电磁目标进行了仿真分析，取得了一系列的关键数据，对于推动目标隐身性能的发展做出了一定贡献。