近距离观察电磁兼容暗室的场均匀性——电磁兼容暗室的有限元分析

A Closer Look at the Field Uniform of Anechoic Chambers——FEM Simulation

采用有限元法(FEM)对电磁兼容暗室的测试面场均匀性(FU)进行了三维仿真分析,目的是比较地面铺设不同吸波材料(仅限于聚氨酯角锥和铁氧体瓦)以及四周墙面安装的吸波材料距离地面20 cm(即与地面相接的四周金属墙面有20 cm裸露在外)时FU的变化情况。计算结果表明:在其他条件相同情况下,仅改进地板铺设的吸波材料性能,可以显著改善FU;而四周墙面铺设的吸波材料离地面有20 cm时,FU将变差。此外,还提供了测试面中的电场三维分布图,使测试面的FU可视化;根据FU分布图分析了FU在较低频和较高频时的不同变化情况。对暗室的三维仿真分析,使得在实际建造暗室之前,就能对暗室的场均匀性有比较准确和具体的了解,从而可以及时发现和解决问题。

An electromagnetic compatibility （EMC） chamber is analyzed by finite element method with regarding to the field uniformity （FU）. The variation of FU with absorbers on the conductive ground, as well as on the four side walls, is studied. The simulated results show that the performance of EMC chambers can be improved greatly by varying the absorbers on the ground, with others condition kept the same; it may get worse if there is 20cm distance of side walls exposed without mounting absorbers. Besides the data in the 16 discrete positions of FU, 3D electric field patterns are provided, which visualize the details of FU area. These results can be a good aid in evaluating the performance of EMC chambers before the chamber is built.