机箱屏蔽效能的积分方程方法建模与仿真技术研究

Shielding with enclosures is common used for the control of electromagnetic interference (EMI). Accurate shielding effectiveness (SE) simulation can directly guide the design and development of electronic products. However, despite the mature commercial software, such as CST、EMC Studio has been used to aiding the SE analysis, numerical simulation still faces many challenges such as too many complicated details, wideband frequency range, and no consistent definiton of shielding effectiveness. Through the deeply research on modeling and simulation with integral equation methods (IEM), this project aims to accurately and effectively evaluate the SE of communication equipment enclosures which may contain lots of holes, sew and PCB boards. Work intended to be carried out includes: (1) research and verification of new definitions on SE, to overcome the limitations of traditional definition in high frequency applications; (2) research on the representative contents (RC) of PCB boards, to alleviate the difficulty and scale of mesh grids in numerical simulation; (3) studying on the hybrid algorithms combined with the accelerated Cartesian expansion (ACE) method and multilevel fast multipole algorithm (MLFMA), to achieve the efficient numerical calculation of integral equation method (IEM) for multi-scale structures with suitable preconditoners; (4) studying on the adaptive frequency sampling (AFS) and interpolating technologies for the fast electromagnetic compatibility (EMC) wideband calculation. The above research outputs, combined with the parallelization calculation, will be useful for the accurate and efficient numerical prediction of shielding effectiveness.The smooth implementation of the project will promote the development of new efficient numerical methods in computational electromagnetics (CEM). The successful application of research outputs in enclosures' SE analysis could also contributes to the progress of EMC simulation.

尽管有CST、EMC Studio等成熟的商业软件辅助分析，机箱屏效仿真仍面临模型结构过于复杂、超宽频带数值计算、观测参量难一致评估等困难。本项目旨在通过对机箱屏蔽效能的积分方程方法建模与仿真技术的研究，实现对含有大量孔、缝、PCB板等细节的通信设备机箱模型的屏效评估。研究工作包括：(1)屏蔽效能新定义的研究及验证，克服传统屏效定义的局限性；(2)PCB板等精细元器件等效模型研究，降低数值仿真时精细结构网格划分的难度与规模；(3)ACE-MLFMA混合算法及与之相适应的预条件算法研究，实现多尺度结构的积分方程快速数值求解；(4)自适应频率采样及插值技术研究，快速实现电磁兼容宽频带计算。并结合并行计算技术，实现复杂机箱结构电磁屏效精确、高效的数值分析和预测。该项目的顺利实施，可促进新的高效数值方法产生，推进计算电磁学领域发展；研究成果在机箱屏蔽方向的应用，也可促进国内电磁兼容仿真行业的进步。

随着工作频率的提高，通信系统面临的电磁干扰问题日益严重。数值仿真是代替试验，对电子设备的电磁干扰特性、电磁兼容性能及防护措施有效性等进行评估的主要手段。针对复杂通信机箱电磁干扰建模和屏蔽效能仿真面临的结构过于复杂、超宽带响应难以评估、仿真与测试难以匹配等困难，本项目对含有大量元器件的复杂通信机箱的电磁干扰及屏蔽效能的数值建模与仿真技术进行研究，提出了测算融合的简化建模方法，基于区域分解实现了干扰源与机箱的协同仿真，并实现了随机信号叠加效应的仿真分析，机箱泄漏场强仿真与测试吻合良好，完成了项目的所有研究内容和论文、软件计划。具体研究成果包括：(1)根据系统设置的不同，提出了不同的屏蔽效能定义形式，并制定了相应的仿真与测试方法；(2)研究了屏蔽通风孔、搭接缝隙等精细结构简化及等效建模方法，降低了复杂机箱数值建模与仿真的复杂度；(3)提出了一种通用性强、稳定性好的自适应频率采样算法，可用较少的采样点插值重构未知函数响应，并结合自适应笛卡尔展开-多层快速多极子算法，实现电大尺寸目标的宽频带电磁特性仿真分析；(4)提出基于机箱的混响室Q值测试理论建立背景传输损耗，准确模拟机箱的真实谐振特性，简化机箱建模，通过测算融合的方法实现仿真与测试的匹配验证；(5)基于等效原理对复杂机箱进行区域分解，实现干扰源的协同仿真，并提出以惠更斯等效面感应电磁流的RWG基函数系数作为传递参数，实现不同电磁算法的协同仿真；(6)以华为公司某产品为例，基于简化建模、测算融合、协同仿真，以及有源叠加，实现了多组连接器多路随机信号传输时，机箱泄漏场强的准确仿真评估。项目提出的等效模型、简化建模方法和快速算法推进了计算电磁学在电磁兼容领域的发展，研究成果在华为技术有限公司的电磁防护与产品设计中得到了工程应用。