【摘要】 电子设备工作频率的提高，导致电磁辐射噪声日益严重，采用屏蔽外壳是最为有效的方法。然而，由于散热和接线，外壳会带有孔洞，极大地影响了其屏蔽效能，部分外壳内部介质板的存在也对屏蔽效能产生了一定的影响。文章对含介质板开孔外壳建模后，通过传输线方法（TLM）建立等效电路模型，然后利用多层自适应交叉算法（Multilayer Adaptive Crossover Algorithm, MLACA）得到等效电路参数，最后根据电压与电场关系计算得到外壳屏蔽效能。利用CST对相应外壳进行仿真分析后，对比屏蔽效能仿真结果和算法结果，证明了该方法结果的准确性和可靠性。通过等效电路模型进一步计算箱内中轴线上各点屏蔽效能，得出屏蔽效果最佳位置分布，最后通过暗室实验测量各点辐射强度来验证预测结果。更多还原

【Abstract】 The increase in the working frequency of electronic equipment leads to the increasingly serious electromagnetic radiation noise, and the use of shielding enclosure is the most effective method. However, due to heat dissipation and wiring, the enclosure will have holes, which greatly affects the shielding effectiveness. The existence of some dielectric plates inside the enclosure also has a certain impact on the shielding effectiveness. In this paper, the equivalent circuit model of perforated enclosure with dielectric plate is established by transmission line method( TLM), and then the equivalent circuit parameters are obtained by Multilayer Adaptive Crossover Algorithm( MLACA). Finally,the shielding effectiveness of the enclosure is calculated according to the relationship between voltage and electric field. After the simulation analysis of the corresponding enclosure by CST, the accuracy and reliability of the results of the method are proved by comparing the simulation results of shielding effectiveness with the algorithm results. Through the equivalent circuit model, the shielding effectiveness of each point on the central axis of the box is further calculated,and the optimal position distribution of the shielding effect is obtained. Finally, the radiation intensity of each point is measured by dark room experiment to verify the prediction results.更多还原