某网络设备EMC 测试超标的分析和结构优化

某设备带插卡EMC测试中辐射超标，文中从插卡PCB和机箱导槽的电容耦合效应入手，分析了EMC测试超标的原因，通过在机箱导槽和PCB之间设计一个铍铜弹性夹片零件，增强了PCB的单板地和机箱之间的电气连接可靠性，从而有效减少了电磁波的电容耦合效应，解决了EMC测试超标问题。同时运用有限元分析方法并进行样品实物测试对比，分析了该铍铜弹性夹片零件在实际生产应用中出现的夹持不可靠问题的原因，并通过更换合适的铍铜材料型号和选择正确的热处理方式解决了该零件的夹持不可靠问题。

Analysis and Structure Optimization for EMC Test Failure of a Network Equipment

A network equipment with pluggable module is failed in EMC test,EM radiation is overrun.Considering the capacitive coupling effect between PCB and guide groove in equipment chassis,the cause of radiation overrun is analyzed.A beryllium copper elastic part is added between PCB and guide groove,the electric connecting reliability between PCB earth and chassis is thus enhanced.Therefore,the capacitive coupling effect is effectively reduced,the problem of radiation overrun is resolved.At the same time,finite element analysis and specimen test are performed,the cause of weak reliability of the beryllium copper elastic part in practical application is found.Weak reliability problem is resolved by choosing the right material type of beryllium copper and the right method of heat treatment.