A three-dimensional numerical model is constructed to predict the EMI shielding performance of a polymer nanocomposite shield in a rectangular waveguide. The Helmholtz wave equation for the electric field is implemented in component form and the set of coupled equations is solved via the finite element approach. Mesh convergence and model verification is performed by comparing free space model predictions for a flat, uniform layer to benchmark solutions calculated via transfer matrix theory. The capability of the model is showcased by exploring the role of geometry on the shielding performance of a sawtooth-shaped composite layer in a rectangular waveguide. Increasing the inclusion angle of the sawtooth, which is proportional to the ratio of the sawtooth amplitude and repeat unit width, reduces the transmitted power through the shield and increases the ratio of absorption to reflection of wave power by the shield. Thus, a rational design of this sawtooth geometry allows to overcome the typical trade-off between total shielding effectiveness and wave absorption contribution, thereby resulting in highly performant absorption-dominated shields.

中文翻译：

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用于预测矩形波导中有损介电聚合物纳米复合材料屏蔽的 EMI 屏蔽性能的整体数值模型：基于吸收的锯齿形层的设计


构建三维数值模型来预测矩形波导中聚合物纳米复合材料屏蔽的 EMI 屏蔽性能。电场的亥姆霍兹波动方程以分量形式实现，并且通过有限元方法求解耦合方程组。通过将平坦、均匀层的自由空间模型预测与通过传递矩阵理论计算的基准解决方案进行比较来执行网格收敛和模型验证。通过探索几何形状对矩形波导中锯齿形复合层屏蔽性能的作用，展示了该模型的功能。锯齿的夹角与锯齿幅度和重复单元宽度的比值成正比，增大锯齿的夹角会降低通过屏蔽的发射功率，并增加屏蔽对波功率的吸收与反射的比率。因此，这种锯齿几何形状的合理设计可以克服总屏蔽效能和波吸收贡献之间的典型权衡，从而产生高性能的吸收主导屏蔽。