基于箱体法材料电磁脉冲场屏蔽效能测试研究

为准确评价屏蔽材料在强电磁脉冲环境中的屏蔽效能,提出了一种基于屏蔽暗箱窗口法的材料电磁脉冲屏蔽效能时域测量方法。该方法将带有测试窗口的屏蔽箱体置于GTEM 室内,被测屏蔽材料安装在屏蔽箱的测试窗口上,利用置于腔体中心的单极子天线测量耦合进腔体的电磁脉冲电压波形,对测得的时域电压信号进行快速傅里叶变换( FFT) ,得到了被测材料频域屏蔽效能曲线。与频域测试结果进行了对比,结果基本一致。实验表明该测试系统可以有效减小局部增强效应对测量精度的影响,能够可靠评价强电磁脉冲作用下材料的屏蔽效能。

Measuring Method of EMP Shielding Effectiveness for a Sealed Metal Box

In order to precisely evaluate the shielding effectiveness in the high-intensity electromagnetic pulse situation, a new time domain measuring method is presented. The shielding cavity with testing aperture is placed in the GTEM cell, the shielding material under test is installed on the testing aperture. The ouput voltage waveform is measured by monopolar antenna placed in middle position of the cavity. The time domain measured signal is applied by FFT, the shielding effectiveness can be obtained by the transformed frequency signal. The calculation shielding effectiveness is similar to the directively measuring result in frequency domain. The experiment results show that new measring method can reduced the influence of the local electric field enhancement to the shielding effectiveness measurement precision, is propitious to precisely evaluate the shielding effectiveness in the high-intensity electromagnetic pulse enviorment.