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在线宽、周期不变(相同透光率)的前提下,增加网栅厚度才能降低网栅的表面电阻,从而进一步提高球面网栅的电磁屏蔽性能。首先推导了网栅厚度、表面电阻和电磁屏蔽效能之间的数学关系,接着开展了膜层增厚的化学镀镍工艺实验。实验结果表明:球面铜网栅上可以得到厚度均匀、结合力牢固的镍磷合金镀层,面电阻由50Ω降至15Ω。经天线法测试,在200 MHz～18 GHz波段,镀镍球面金属网栅膜屏蔽效能平均达到46 dB,比未镀镍前平均提高了8 dB,而球面网栅试件镀镍前后,在400～900 nm波段透过率均为88%。镀镍前后透过率基本相同时,镀后表面电阻迅速降低,电磁屏蔽效能得到了显著提高。
On the premise of constant bandwidth and same period (same transmittance), increasing the grid thickness can reduce the surface resistance of the grid and further improve the electromagnetic shielding performance of the grid. The mathematical relationship between grid thickness, surface resistance and electromagnetic shielding effectiveness was deduced firstly. Then the experiment of electroless nickel plating with thicker film was carried out. The experimental results show that the surface resistance can be reduced from 50Ω to 15Ω on the spherical copper grid with uniform thickness and strong adhesion. According to the antenna test, the shielding effectiveness of the nickel-plated spherical metallic grids reaches 46 dB on average in the band of 200 MHz to 18 GHz, which is an average of 8 dB higher than that before the nickel-free plating. At 400 Transmittance at ~ 900 nm band is 88%. Before and after the nickel penetration rate is basically the same, after plating rapid reduction of surface resistance, electromagnetic shielding effectiveness has been significantly improved.