一种基于BLT方程的孔缝箱体屏蔽效能计算方法

本文基于等效电路法, 提出一种通过BLT方程计算带孔缝箱体屏蔽效能的方法, 可以快速准确计算任意入射、极化平面波照射箱体以及任意位置开孔和双面开孔箱体的屏蔽效能. 根据等效电路法求解出孔缝散射矩阵, 依据信号流图建立传播关系和散射关系方程, 并推导出包含孔缝耦合效应的广义BLT方程. 将BLT方程计算结果与等效电路法计算结果以及CST仿真做对比, 验证了方法的正确性. 与等效电路法相比, 在同一孔阻抗下, 孔缝散射矩阵包含箱体内外能量之间的相互耦合作用, 本方法计算结果精度更高, 能预测更多箱体谐振模式; 与CST仿真相比, 本方法占用时间和资源少, 可以对箱体参数进行规律性研究.

A BLT equation-based approach for calculating the shielding effectiveness of enclosures with ap ertures

A calculation method based on BLT equation is proposed for analyzing the shielding effectiveness of enclosures containing apertures. This method can accurately and quickly obtain the shielding effectiveness of oblique incidence and polarization, off-centered apertures, and multi-apertures in two walls of enclosures. Aperture scattering matrix can be obtained according to equivalent circuit theory. Then, propagation relationships and reflection relationships are established, and finally the general BLT equation is derived, including the coupling to apertures. In order to verify the validity, the results are compared with these from equivalent circuit theory and CST. With the same aperture impedance, the aperture scattering matrix contains the interaction of the electromagnetic field so that the method proposed in this paper owns higher precision and can predict more resonant modes compared with the equivalent circuit theory. This method takes less time and computer resource compared with CST which cannot easily get the influence of enclosure parameters.