Equivalent Circuit and Damage Threshold Study of Communication Interfaces under HEMP

In a strong electromagnetic pulse environment, high-intensity, broadband electromagnetic pulse energy is transmitted to the communication interface circuit through the interconnection cable, causing interference or damage to the internal electronic components and chips, and even posing a serious threat to the entire communication equipment. Based on the field line coupling model, the coupling effects of communication device interfaces under different terminal impedances are studied in this paper. By establishing the coupling circuit model of RS-232 interface under HEMP, and combining with pulse injection experiment, the equivalent circuit model of RS-232 interface is accurately determined, and the damage threshold of the sending end of RS-232 interface under HEMP is obtained. Compared with the measured data before and after the interface damage, the accuracy of the model and the reliability of the modeling method are verified, and the two agree well. The proposed interface equivalent circuit model can not only accurately characterize the coupling effect of communication equipment interface under the action of strong electromagnetic pulse, but also provide simulation level support for the subsequent design of communication equipment interface protection circuit. This method can be extended to different types of strong electromagnetic pulse and communication interfaces, and has a good application prospect.