On the basis of the characteristics of the heterotypic metallic enclosure with a built-in dielectric plate, this paper proposes an analytical method to evaluate the shielding performance of an apertured enclosure with convex or stepped structure under the plane wave illumination. First, the heterotypic enclosure is modeled based on the electromagnetic topology (EMT) theory, where the scattering parameter matrix at the discontinuous position can be derived according to the theory of microwave circuit. Then, the expressions of total voltage components can be obtained by using the extended Baum-Liu-Tesche (BLT) equation, which are convenient to calculate the SE at the monitor point. Finally, the effectiveness and accuracy of the proposed method in predicting the shielding effectiveness (SE) and resonances of heterotypic enclosure are verified by the computer simulation technology (CST) through several cases. Compared with the CST simulation, the proposed method is more efficient and takes up less memory.

根据内置介质板的异型金属外壳的特点，提出了一种分析方法来评估具有凸面或阶梯结构的带孔外壳在平面波照射下的屏蔽性能。首先，基于电磁拓扑（EMT）理论对异型外壳进行建模，其中根据微波电路理论可以推导出不连续位置处的散射参数矩阵。然后，可以通过使用扩展的Baum-Liu-Tesche（BLT）方程获得总电压分量的表达式，该方程便于在监视点处计算SE。最后，计算机模拟技术（CST）通过几个案例验证了所提出的方法在预测异型外壳的屏蔽效率（SE）和共振方面的有效性和准确性。与CST仿真相比，该方法效率更高，占用内存更少。