屏蔽体孔缝对雷电流屏蔽效能的影响

Influence of Shield Slot on Shielding Effectiveness of Lightning Current

针对孔缝屏蔽腔内传输线上耦合雷电波的特性研究问题,对孔缝金属腔体屏蔽效能的理论分析,利用雷电试验冲击平台(ICGS)模拟产生雷电注入金属杆后模拟辐射雷电电磁波进行孔缝金属腔体屏蔽效能的实验。在孔缝数量一定时改变孔缝直径分析雷电电磁波进入金属腔体的特性。实验表明:金属腔体内部的天线接收到的电磁波信号基本上都是小于腔体外部的天线接收到的电磁波信号,即金属腔体对于雷电波产生的电磁波有屏蔽作用;改变孔径的大小,得出腔体的孔缝直径越小,雷电电磁信号对腔体的屏蔽效果越好范围为16.5dB-18dB之间;当金属腔体表面的孔缝直径一定时,改变金属腔体表面的孔缝数量,根据实验数据得出金属腔体表面的孔缝数量越少对雷电电磁波进入腔体的屏蔽效能越好,范围也是在16.5dB-18dB之间。根据屏蔽效能曲线的一次线性拟合方程得出随着雷电电流的增大,屏蔽效能有略微的减小,此现象是由于雷电电磁信号进入金属腔体内并在腔内发生多次折反射,使得屏蔽效能减小。

Aiming at the problem of coupling lightning wave characteristic study on the transmission line in the aperture shielding cavity, the shielding effectiveness of the slotted metal cavity is analyzed theoretically, and the lightning impulse platform （ICGS） is adopted to simulate the lightning electromagnetic wave experimental study on shielding effectiveness of porous metal cavity. When the number of holes is fixed, the diameter of aperture is c lightning electromagnetic wave entering metal cavity. The hanged to analyze the characteristics of experimental results show that the electromagnetic wave signal received by the antenna inside the metal cavity is basically smaller than the electromagnetic wave signal received by the antenna outside the cavity, that is, the metal cavity has the shielding effect on the electromagnetic wave generated by the lightning wave; The smaller the aperture diameter of the cavity, the better the shielding effect of the lightning electromagnetic signal to the cavity is between 16.5dB-18dB; when the hole diameter of the metal cavity surface is constant, change the aperture of the metal cavity surface The number of holes on the surface of the metal cavity surface the less the number of lightning electromagnetic wave into the cavity of the shielding effectiveness of the better range is between 16.5dB-18dB. According to a linear fitting equation of shielding effectiveness curve, it is concluded that the shielding effectiveness decreases slightly with the increase of lightning current. This phenomenon is due to the fact that the lightning electromagnetic signal enters into the metal cavity and many fold reflections occur in the cavity, shielding effectiveness is reduced.