开缝腔体场强增强效应抑制方法研究

开缝屏蔽腔体不能完全阻断能量耦合,导致在腔内局部区域、特定频点附近形成场强增强效应,对敏感器件或线路构成威胁。以分析腔内场强增强效应及研究抑制方法为出发点,建立3 种开缝腔体数值模型,提出并验证腔体涂覆吸波材料、内置吸波柱、内置双层PCB 板等谐振抑制方法的有效性。结果表明:在3 种腔体模型内表面涂覆吸波材料均能有效抑制场强增强效应,并且涂覆磁损耗型吸波材料效果最好;随着涂覆厚度的增加,谐振抑制效果也增强;腔体中心放置吸波柱,应使用电损耗型吸波材料。腔体内置PCB 板既能实现对电子器件和线路的承载功能,还可整体大幅度提升腔体屏蔽效能,对谐振效应的抑制体现在迫使腔体主谐振点偏移,结合使用吸波材料,高阶第2 谐振点处谐振抑制效果也明显改善。

Study on the Inhibition Method of Field Enhancement Effect for the Slotted Cavity

Because the slotted cavity can not block the energy coupling completely, it results in field enhancement effect in the local area and the specific frequency points. This poses a threat to sensitive devices or circuits. Based on the analysis of field enhancement effect and inhibition method, three numerical models of slotted cavity are established. The effectiveness of resonance suppression method, such as coated absorbing material, built-in absorbing column and built-in double layer PCB board, is proposed and verified. The results show that the absorbing material can effectively inhibit the field enhancement effect in the three cavity models. The coated magnetic loss absorbing material has the best effect. With the increase of coating thickness, the effect of resonance suppression is also enhanced. The electrical loss absorbing column should be used in the center of the cavity. The built-in PCB board can not only realize the bearing function of electronic devices and lines, but also enhance the shielding effectiveness. The resonance suppression effect is reflected in forcing the offset of the main resonance. Cooperating with absorbing material, the suppression effect of high-order resonance is also improved significantly.