金属腔体多耦合通道电磁特性研究

Study on Electromagnetic Characteristics of Multi-coupling Channels for the Metal Cavity

实际金属腔体常开有多个通道,使得腔内电磁环境变得复杂。以分析腔体多通道耦合电磁特性为出发点,建立平面波入射下矩形、圆柱腔体实例模型,引入对比系数作为评价手段,侧重研究孔缝、贯穿线缆两种耦合通道对腔内电磁场的影响,寻求共性规律。结果表明:腔外线缆长度变化不影响谐振点出现位置,随长度增加腔体屏蔽效能(SE)下降;腔内线缆随长度增加,谐振频率降低,两腔体具有如上共性结论。基于给定的模型及参数设定,通过比较系数可判断矩形腔体450 MHz之前线缆耦合为主;贯穿线较长时,510 MHz之前圆柱腔体线缆耦合为主;贯穿线较短时,两个局部频点之外的其它频段孔缝耦合为主;涂覆磁损耗型吸波材料提升腔体SE效果最好,且SE越低,提升效果越明显。

The actual metal cavity has multiple channels,which makes the electromagnetic environment complicated.Based on the analysis of the electromagnetic characteristics of multi-coupling channels,the rectangular and cylindrical cavity models under plane wave incidence are established.Comparison coefficient is introduced as an evaluation method.The effects of slot and through-cable coupling channels on the electromagnetic field are the focus of research.The results show that:the change of cable length outside the cavity does not affect the position of resonance point,but the shielding effectiveness(SE)decreases with the increase of the length;the resonant frequency decreases with the increase of the cable length of inside cavity;the two cavities have the same conclusion.Based on the given model and parameter setting,the cable coupling is dominant before 450 MHz of rectangular cavity can be judged by comparing coefficient.When the cable is long,cable coupling is dominant before 510 MHz.The aperture coupling is dominant besides two local frequencies when the cable is short.The effect of SE lifting by coating magnetic loss absorbing material is the best,and the lower the SE,the better the effect.