光学窗口电磁屏蔽性能分析与验证

为分析不同基底材料光学窗口电磁屏蔽性能，以Kohin的等效薄膜模型为基础，考虑电磁波在材料2个界面中的多次反射和折射，得到电磁波界面反射系数，利用matlab编写程序计算相同网栅、不同厚度、不同材料的屏蔽效率曲线，分析了厚度和材料对光窗屏蔽效率的影响。为验证仿真数据的准确性，在ZnS基底上制作了周期为500 μm、线宽为15 μm，电阻≤20 Ω的测试样片，测试其在8 GHz～18 GHz频段的电磁屏蔽效能。通过对比可看出:测试与理论计算数据较符合，误差约为2 dB～4 dB，计算数据可以预估光学窗口电磁屏蔽性能，为后续的设计工作提供参考。

Analysis and test of electromagnetic shielding effectiveness of optical window

In order to analyze the electromagnetic shielding performance of optical windows of different substrate materials,based on Kohin's equivalent thin film model,the electromagnetic wave interface reflection coefficient was obtained considering the multiple reflections and refractions of electromagnetic waves between two interfaces in material.The matlab was used to calculate the shielding efficiency curves of the same mesh,different thicknesses and different materials,and the influence of thickness and material on the shielding efficiency of the light windows was analyzed.To verify the correctness of the simulation data,the metallic mesh with line width of 15 um,period of 500 um and resistance of≤20Ωwas fabricated on ZnS,and the shielding effectiveness at 8 GHz^18 GHz was tested.Comparison results show that the testing results are in good agreement with the theoretical calculation data,and the error of the curves is about 2 dB to 4 dB.The result can estimate the shielding effectiveness of optical windows with metallic mesh coating,which canprovide references for the shielding effectiveness of optical window design subsequently.