孔缝对航空器电子设备舱屏蔽效能的影响

Influence of Apertures in the Avionics Cabin on Electromagnetic Shielding Effectiveness

应用全域基函数表示缝隙场技术的矩量法,分析计算矩形屏蔽体的屏蔽效能。基于缝隙切向电磁场连续条件,通过求解腔体格林函数得到屏蔽体内部场强。通过对经典孔缝电磁耦合模型的数值仿真,得出的结论与已有文献和实验结果吻合良好。验证了该算法的准确性和计算效率。仿真结果表明:孔缝的形状、入射波极化方向和屏蔽体内不同计算点等因素对屏蔽效能影响很大。通过数值仿真得出的规律性结论,有利于指导屏蔽体孔缝形状的设计以及敏感器件和设备的合理布局。因此屏蔽效能的仿真分析在民用航空电子系统防护高强度辐射场的工作中具有重要的指导意义。

Electric field shielding effectiveness of metallic enclosure with apertures when illuminated by different polarization plane wave have been studied by using modal method of moment technique. Electric field shielding effectiveness of enclosure with different shape apertures and same area has been calculated at different points inside the enclosure. To achieve this, assuming appropriate electric field distribution on the aperture, fields inside the cavity are determined using rectangular cavity Green＇ s function. Electromagnetic fields outside the cavity and scat-tered due to the aperture are obtained using the free space Green＇ s function. Matching the tangential magnetic field across the apertures, the integral equation with aperture fields as unknown variables is obtained. A very good agreement among the results of the proposed technique, results available in the literature and experimental results is observed. The results also show that the electric field shielding effectiveness is seriously affected by calculation points, the shape of apertures and polarization of the illuminating field.