高通光率金属网栅屏蔽效率分析的等效折射率模型

Equivalent refractive index model on shielding effectiveness analysis of high transparency metallic mesh

基于Ulrich半实验方法、LZ等效电抗模型和Kohin等效膜方法，建立了一种新型的高通光率金属网栅屏蔽效率分析的等效折射率模型。该模型精确地建立了金属网栅的等效折射率与其结构参数和边界材料折射率的关系，便于分析电磁波任意入射方向时的金属网栅屏蔽效率，并可克服Chen倾斜模型在分析高通光率金属网栅屏蔽效率时的失效问题。为验证建立模型的有效性，用紫外光刻法制备了周期320μm、线宽4．5μm和周期160μm、线宽5．5μm的两种网栅，并用微波网络分析仪测试了12-18GHz波段的屏蔽效率。实验与分析表明：建立的新模型的原理计算误差〈2dB，优于Chen模型和LZ模型的8dB的原理计算误差和Ulrich模型的4dB的原理计算误差，说明新模型能更精确地分析高通光率金属网栅的屏蔽效率。

A novel equivalent refractive index model of high transparency metallic mesh was proposed to calculate its shielding effectiveness accurately. Based on Ulrich＇s empirical method, LZ＇s equivalent reactance model and Kohin＇s equivalent film method, the model accurately established the relation among mesh equivalent refractive index, structural parameters and dielectric boundary refractive indexes so that it is easy to calculate the mesh shielding effectiveness under various incident angles and to prevent the invalidation of Chen＇s formulas about oblique incidence on high transparency. To identify the new model＇s validity, two kinds of metallic meshes in period of 160 μm, line width of 5.5 μm and period of 320 μm, line width of 4.5 μm were fabricated using UV-lithography, and the shielding effectiveness were measured by microwave network analyzer at 12-18 GHz. Experiment and analysis show that the new model＇s theoretical calculation error is less than 2 dB, more accurately than 4 dB of Ulrich＇s model and 8 dB of Chen＇s and LZ＇s models.