基于屏蔽室法的材料电磁屏蔽效能的简易测试方法及影响因素分析

发布时间：2018-11-20 09:28

【摘要】：各种电子、通信等设备在使用过程中产生大量的电磁辐射,会对人员及其他设备产生电磁干扰和损害。电磁屏蔽作为解决电磁干扰问题的一个重要手段,越来越被重视。起初的电磁屏蔽材料多为金属材料,例如铜、铝等,其共同特点是具有很高的电导率,屏蔽效果很好。但这类材料质量很大,不具有轻便性,并且在空气中易被氧化和腐蚀,制造成本也比较高。随着近年来材料科学技术的发展,非金属复合型材料,如导电橡胶、导电涂料等逐渐替代金属材料被用作屏蔽材料使用。这类材料造价较低,并且具有良好的适形特性和可塑性,在电磁密封等特殊应用场合有独特优势。但这类复合型材料的电导率都相对较低,所以对其屏蔽效能的测试显得尤为重要。现阶段相关标准中规定的材料屏蔽效能测试方法主要适用于高频段(10kHz以上),并且测试设备造价昂贵,使用复杂。本文在第一部分工作中设计研发了一套用于测量材料在低频电场中屏蔽效能的方法和装置,弥补了现有标准的不足。本方法使用市电电源(220V/50Hz)、带有测试窗口的屏蔽体、自制的极板、电阻和万用表,结构简单,操作简便,成本低廉,具有良好的操作简便性和经济性。通过试验,本文研究了可能影响工频电场中材料屏蔽效能测试的一些因素。本文的第二部分工作是根据标准GJB 6190-2008,结合屏蔽室法和法兰同轴法各自的特点,设计研发了一套用于测量材料在高频电磁场中屏蔽效能的装置和方法。本方法使用简单的自制天线结合网络分析仪使用,具有良好的经济性和操作简便性。通过试验,本文研究了可能影响高频电磁场中材料屏蔽效能测试的一些因素。
[Abstract]:A large amount of electromagnetic radiation is produced in the process of use of various electronic, communication and other equipment, which will cause electromagnetic interference and damage to personnel and other equipment. As an important means to solve electromagnetic interference, electromagnetic shielding has been paid more and more attention. At first, the electromagnetic shielding materials are mostly metal materials, such as copper, aluminum, etc. Their common characteristics are that they have very high conductivity and the shielding effect is very good. But this kind of material is of high quality, not light, and easy to be oxidized and corroded in air. With the development of material science and technology, nonmetallic composite materials, such as conductive rubber and conductive coatings, have been used as shielding materials. This kind of material has the advantages of low cost, good conformability and plasticity, and has unique advantages in special applications such as electromagnetic sealing. However, the conductivity of these composite materials is relatively low, so it is very important to test their shielding efficiency. At present, the testing method of material shielding effectiveness stipulated in relevant standards is mainly suitable for high frequency band (10kHz or above), and the testing equipment is expensive and complex to use. In the first part of this paper, a set of methods and devices for measuring the shielding effectiveness of materials in low frequency electric field are designed and developed, which make up for the deficiency of existing standards. The method is simple in structure, simple in operation, low in cost, and has good operation simplicity and economy, using 220V/50Hz, shielding body with test window, self-made pole plate, resistance and multimeter. In this paper, some factors which may affect the shielding effectiveness of materials in power frequency electric field are studied. In the second part of this paper, according to the standard GJB 6190-2008, combined with the characteristics of the shielding chamber method and the flange coaxial method, a set of devices and methods for measuring the shielding effectiveness of materials in high frequency electromagnetic field are designed and developed. This method uses simple self-made antenna combined with network analyzer, and has good economy and easy operation. Some factors which may affect the shielding effectiveness of materials in high frequency electromagnetic field are studied by experiments.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN03

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