大型天线阵列与多层天线罩一体化高效全波数值算法研究

Scattering/radiation analysis of antenna array with radome is a key step in modern stealth aircraft design, and it has brought several challenges to the development of computational electromagnetics: (1) Practical antenna arrays are always large with hundreds or thousands of complex shape units. They are usually composite objects containing different dielectric materials. (2) The presence of thin dielectric substrate or metal patches, cracks and other tiny structures require very fine meshes to achieve accurate results, causing multi-scale problems. (3) Radome is usually an electrical large object containing multi layers of homogeneous dielectric structures. Even full-wave numerical simulation of a single radome itself is a great challenge. When putting together with a practical antenna array, especially for the case all the dielectric materials are lossless, the final matrix equation system obtained is not well conditioned. It cannot be solved efficiently or even failed to converge when iterative solvers are adopted. Existing full-wave methods are difficult to achieve a general, efficient and accurate solution for such case and new methods are required. To overcome the difficulties confronted in scattering/radiation analysis of antenna array with a radome, the project commenced research and the main contents are: (1) Develop a new formulation of hybrid finite element-boundary integral-multilevel fast multipole algorithm. (2) Construct an efficient preconditioner to speed up iterative solution of the final matrix equation system of the hybrid method. (3) Develop an efficient and easily parallelized domain decomposition based H-LU solver for the direct solution of the proposed preconditioner. (4) Parallelize the proposed approach with the Message-Passing Interface (MPI) to further strength its capability for practical structure. The project intends to study the above key technical breakthrough and then solve the antenna array with radome scattering/radiation problem in practical engineering.

天线、天线罩一体化分析是飞行器设计的关键，也是计算电磁学挑战性问题：（1）实际天线阵列规模庞大，结构复杂，通常为介质与金属复合。（2）存在极薄介质基片或金属贴片、缝隙等需细密剖分的细微结构，形成多尺度问题。（3）天线罩通常为多层、电大介质体，本身便是计算电磁学的挑战性问题。与天线阵一体化计算，特别是当天线罩介质材料无吸收或损耗极小时，形成矩阵方程迭代求解收敛性极差甚至不收敛。现有全波算法很难实现此类问题的通用、高效求解。本项目针对此类问题展开研究，主要内容有：（1）开展新型混合有限元、边界积分方程、多层快速多极子技术研究；（2）针对混合方法最终形成矩阵方程，构建高效预处理矩阵；（3）研究高效、易于并行的区域分解型H-LU预处理矩阵直接求解技术；（4）开展基于MPI的高效并行化实现研究，提高对实际目标仿真能力。本项目拟通过以上关键技术的研究突破，解决实际工程中的天线、天线罩一体化计算的难题。

天线是电磁波发射或接收系统的关键部分，是雷达、通信、电子战等现代电子设备不可或缺的一部分。单纯天线的仿真计算是电磁场与微波技术领域十分成熟的技术。然实际装载平台环境中，机载天线通常采用由多层介质材料，如硬质玻璃组成，具有良好的透波特性的天线罩。天线、天线罩一体化分析是计算电磁学的挑战性问题，其挑战性主要体现在实际天线阵列规模庞大，存在极薄介质基片或金属贴片、缝隙等需细密剖分的细微结构，天线罩通常为多层、电大介质体结构。现有全波算法很难实现此类问题的通用、高效求解。.本项目针对天线-天线罩一体化快速仿真问题展开研究，首先开展了新型混合有限元、边界积分方程、多层快速多极子技术研究，通过采用积分方程替代原有的有限元体计算区域，减少了未知数规模。之后，针对混合方法最终形成矩阵方程性态不佳，收敛性差的问题，基于H-matrix快速直接求解技术，构建了基于H-LU的高效预处理器。最后，对整个方法开展基于MPI和OpenMP的高效并行化实现研究，借助并行求解技术，提高对实际目标仿真能力。在项目研究过程中，重点对H-LU快速直接求解技术、并行化实现开展了技术突破，开发出了高效的混合算法，初步具备对实际工程中的千单元规模天线阵列、天线罩的一体化并行计算的能力。.本项目的研究成果可直接应用于隐身飞行器天线-天线罩一体化的低RCS设计仿真优化，经进一步优化发展后，可用于天线与平台一体化辐射性能分析，并为相关应用单位实际工程设计提供有力工具。本项目研究成果发表论文9篇，其中SCI论文5篇，本专业顶级期刊IEEE TAP 3篇。算法理论创新推动了相关研究工作的发展。