Fabrication of Composite Structure Metal Grid and Study on Its Infrared Transparency and Electromagnetic Shielding Characteristics

For the current requirements of electromagnetic shielding performance of infrared transparent devices in optoelectronic systems, this paper uses High Frequency Structure Simulator (HFSS) simulation software to simulate the electromagnetic shielding effectiveness (SE) of metal mesh grids with different mesh cycles, mesh line widths, substrate materials and substrate thicknesses, and analyzes the influence of each parameter on the performance of metal mesh grids. The influence of each parameter on the performance of metal mesh grating is analyzed. The simulation results show that the electromagnetic shielding effectiveness and infrared transmittance of single-layer metal mesh grids are contradictory to each other. In order to take into account the electromagnetic shielding effectiveness and infrared transmittance, this paper designs double-layer metal mesh grids with different structures, simulates their electromagnetic shielding effectiveness, investigates the factors affecting the electromagnetic shielding effectiveness of double-layer metal mesh grids, and then prepares double-layer metal mesh grids with a period of 600 μm and a line width of 20 μm. The performance of the prepared double-layer metal mesh grille is tested by using a vector network analyzer and a vacuum type Fourier transform infrared spectrometer, and the measured transmittance of the double-layer metal mesh grille in the 3 μm−5 μm band is about 86.5%, and the average shielding efficiency in the 12 GHz−18 GHz band reaches 25 dB, which is 2.5% lower than that of the single-layer metal grid grille but the SE is improved by 10 dB. Based on the comparison and analysis of the measured and simulated results of the metal mesh grille, the reasons affecting the measured results are given.