孔阵腔体屏蔽效能BLT方程修正与拓展分析

Modification and Expansion Analysis of BLT Equation for Shielding Effectiveness of Aperture Array Enclosure

以中心位置携带孔缝的机载电子设备屏蔽腔体为研究对象,建立能够计算平面波辐照下腔体屏蔽效能的BLT(Baum-Liu-Tesche)方程。针对Robinson孔阵阻抗计算误差较大这一问题,引入偏心系数C mk修正孔阵阻抗,修正后BLT方程能准确计算开有任意位置孔阵腔体的屏蔽效能。通过对电磁波电场进行矢量分解,实现了任意极化角度下屏蔽腔体屏蔽效能的计算。结果表明,屏蔽腔体屏蔽效能随孔缝数量的增加而升高,极化角度的增大会增强屏蔽腔体电磁屏蔽能力。将BLT方程计算结果与Robinson法结果、CST仿真结果进行对比,证明BLT方程具有准确性,为计算机载电子设备屏蔽腔体屏蔽效能提供了一种有效方法。

Taking the shielding enclosure of airborne electronic equipment with apertures and slots in the center as the research object,a BLT(Baum-Liu-Tesche)equation which can calculate the shielding efficiency of the enclosure under plane wave irradiation is established.Aiming at the problem of large error in Robinson aperture array impedance calculation,the eccentricity coefficient Cmk is introduced to modify the aperture array impedance,and the modified BLT equation can accurately calculate the shielding efficiency of the enclosure with aperture array at any position.The calculation of shielding effectiveness of shielding enclosure at any polarization angle is realized by vector decomposition of electromagnetic wave electric field.The results show that the shielding effectiveness of the shielding enclosure increases with the increase of the number of apertures and slots.The increase of polarization angle enhance the electromagnetic shielding ability of shielding enclosure.By comparing the calculation results of BLT equation with the results of Robinson method and CST simulation,it is proved that BLT equation is accurate,which provides an effective method for the shielding effectiveness of shielding enclosure of computer-borne electronic equipment.