带孔阵屏蔽腔电磁屏蔽特性的时域有限元分析

Analyses on the Electromagnetic Shielding Properties of Enclosure with Aperture Array Using Finite-Element Time-Domain Method

为了分析带孔阵屏蔽腔的电磁屏蔽性能,使用变分法推导了适用于内部辐射源情况下屏蔽腔屏蔽分析的时域有限元算法,并将集总电阻加入到时域有限元代码中用于消耗系统的能量和加快其衰减速度。计算了系统的传输功率以及3 m远处的电场值,并和测试结果及商业软件仿真结果进行了对比,结果吻合良好。基于频域结果分析了屏蔽腔不同谐振模式和工作频率对其屏蔽性能的影响。最后,将损耗材料加入屏蔽腔中降低其品质因数和谐振效应,时域有限元算法证明了该方法的有效性。

In order to investigate the electromagnetic shielding performance of enclosure with aperture array, finite-element time-domain （FETD） formulations which are suitable for inner excitation cases are derived by using variation principle. The lumped resistor is incorporated into FETD code to appropriately consume the system energy and accelerate the process of energy decay. Meanwhile, the delivered power and electric field 3 meters away from the enclosure are calculated and compared with the measurement results or commercial software results and they agree well with each other. Moreover, the analysis on the influence of the various resonant modes and the operation frequency on the shielding performance of the enclosures are conducted based on the frequency-domain results. Finally, the lossy material is placed into enclosures to decrease the quality factor and alleviate resonance. The effectiveness of this method is verified by FETD computational results.