一种测试材料在工频电场中的屏蔽效能简易方法

A Simple Method for Measuring the Shielding Effectiveness of Composite Material Against Low Frequency Electric Field

复合型的导电材料,虽然导电性不如金属材料,但由于其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。复合型材料在工频电场中的屏蔽效能评估是一个重要的问题,现阶段国内外对测试材料电磁屏蔽效能的方法,主要是国军标GJB 6190—2008给出的2种方法:屏蔽室法和法兰同轴法。其中,屏蔽室法需要用到一系列测量设备,包括发射天线、接收天线、功率放大器等,这些设备造价昂贵且使用起来较为复杂,同时屏蔽室法的测量范围为10 k Hz^40 GHz,没有涵盖到10 k Hz以下的频率范围;法兰同轴装置需要结合网络分析仪使用,且一般适用于30 MHz^1.5 GHz的频率范围,同样法兰同轴法不能用于工频电场屏蔽效能测试。该文提供一种操作简单、成本低廉的测试方法用于测试电磁屏蔽材料在工频电场中的屏蔽效能,弥补了现有屏蔽材料屏蔽效能测试方法的不足。

Composite materials have less conductive low conductivity than metal materials, but they have some characteristics like good flexibility and plasticity, which make them have unique advantages for some special applications such as electromagnetic sealing. The shielding effectiveness of composite material in low frequency electric field is one of the most important problems. Nowadays the primary methods for measuring the shielding effectiveness of composite material at home and abroad are method of shielding enclosures and method of coaxial planar which are given in the standards of GJB 6190--2008. Many equipment are used in the method of shielding enclosures, including the transmitting antenna, receiving antenna, power amplifier etc. and so on. The equipment are expensive and not simple, and the measuring range is between 10 kHz and 40 GHz, which can not be used in the field with the frequency 50 Hz. In the coaxial flange method, network analyzer is required and the operating frequency is usually between 30 MHz and 1.5 GHz. An simple testing method of electromagnetic shielding effectiveness of composite material in 50 Hz electric field is given in this paper, which is low cost and can compensate for the weaknesses of existing testing methods.