Research On Preparation And Performance Of Broadband Electromagnetic Shielding Glass

With the wide application of electromagnetic equipment in electromagnetic technology,people’s demand for electromagnetic shielding materials is increasing.Electromagnetic shielding glass has both electromagnetic shielding performance and visible light transmittance.It has clear application requirements in the military and civil fields.The research on electromagnetic shielding glass has become one of the hotspots of shielding material research.Aiming at the technical problems of high-efficiency electromagnetic shielding in the 10 k Hz～18 GHz wide frequency band,this paper has prepared and studied a high-frequency electromagnetic shielding ITO coated glass and low-frequency electromagnetic shielding iron-nickel alloy coated glass,and designed and verified a composite broadband electromagnetic shielding glass.The main research contents and conclusions of this paper are as follows:(1)ITO coated glass was prepared by magnetron sputtering method and its photoelectric properties and electromagnetic shielding performance were studied.On this basis,the electromagnetic shielding performance of multilayer ITO coated glass was studied.The results show that the electromagnetic shielding performance of ITO coated glass in the high frequency band of 30 MHz～18 GHz is better,and it is maintained at about 30 d B,but the shielding performance of the low frequency band of10 k Hz to 30 MHz is less than 20 d B.The smaller the sheet resistance,the better the electromagnetic shielding performance,and the sheet resistance value is obviously inversely proportional to the film thickness.Multi-layer ITO structure can significantly improve the high frequency electromagnetic shielding performance of coated glass,reduce its light transmittance,but does not affect its haze.(2)The Fe-Ni alloy coated glass was prepared by the vacuum electron beam evaporation method,and the effects of different vacuum degrees,coating temperatures and heat treatment temperatures on the optical,electrical and magnetic properties of the coated glass were studied,and tested the shielding performance of the Fe-Ni alloy coated glass prepared under the optimal coating process and heat treatment process.The results show that the increase in vacuum and coating temperature can improve the transmittance,sheet resistance and relative permeability of the coated glass.As the film thickness increases,the sheet resistance of the iron-nickel alloy coated glass decreases rapidly,and the relative permeability increases slightly.,and the light transmittance gradually decreases,and the haze changes little.The heat treatment increases the crystallinity of the film.As the heat treatment temperature increases,the light transmittance of the Fe-Ni alloy coated glass gradually increases,the sheet resistance value first decreases and then increases,and the sheet resistance value is the smallest when heat-treated at 300 °C.The shielding effectiveness of Fe-Ni alloy coated glass in the low frequency electromagnetic wave frequency band of 10 k Hz～30 MHz is relatively high,maintaining above 30 d B,and reaching 55 d B at 14 k Hz.The shielding efficiency is higher in the higher frequency range of 30 MHz～18 GHz.The shielding effectiveness is low,generally below 30 d B.(3)Design the structure of broadband electromagnetic shielding glass and verify its electromagnetic shielding performance.The results show that: ITO and Fe-Ni alloy composite structure electromagnetic shielding glass can be used for broadband electromagnetic shielding from 10 k Hz to 18 GHz.The shielding effectiveness simulation result is above 40 d B,the actual test result is slightly lower,about 30 d B or more,and some frequency bands can reach up to 45 d B or more.Affected by the light transmittance of iron-nickel alloy coated glass,the light transmittance of composite structure coated glass is low,and it can be solved by adopting more mature film hollowing technology in the future.