Design And Research Of Combined Protection Module Of Strong Electromagnetic Pulse

Strong electromagnetic pulse usually enters the wireless communication equipment through two coupling paths: front door(antenna)and back door(slot,cable,etc.),resulting in degradation or even damage of its working performance.In view of the shortcomings of the existing general protection module in the protection ability of strong electromagnetic pulse,this paper designs a new type of combined protection module of strong electromagnetic pulse,which adopts the method of combined protection of transient protection and steady-state protection,designs the combined protection module of strong electromagnetic pulse for wireless communication equipment,and completes the radio frequency link,network line and audio line of ultrashort wave radio It is very important for wireless communication equipment to work normally under strong electromagnetic pulse environment.In the first part,the time-frequency characteristics of several kinds of strong electromagnetic pulses are studied,and the spectrum energy distribution of several kinds of strong electromagnetic pulses is determined.Taking the RF link of ultrashort wave radio as an example,the coupling path of strong electromagnetic pulses is analyzed,and the internal transmission link and sensitive elements are studied.The transmission characteristics of common external interconnection cables,such as the working voltage and frequency band of network cable and audio cable,are analyzed According to the requirements of MIL-188-125-2 Appendix B protection module pulse current injection test and GJB8848 system electromagnetic environment effect test method,the design index of combined protection module of strong electromagnetic pulse is determined.In the second part,the protection mechanism and key protection parameters of several commonly used transient suppressors are studied,and the response characteristics of transient suppressors under the strong electromagnetic pulse are explored by using the existing strong electromagnetic pulse testing equipment in the laboratory.The change rules of several key protection parameters of transient suppressors under the high altitude nuclear electromagnetic pulse are given in detail,and the transient suppressors of Junyao company are used As an example,combining with the equivalent circuit model of transient suppressor in related papers,the PSPICE equivalent circuit correction model is established in cadence,and compared with the test results.The simulation results are basically consistent with the measured results,which verifies the accuracy of the modified model.In the third part,the transient circuit design technology of the combined protection module of strong electromagnetic pulse is studied.The selection methods of several transient suppression devices under different pulses and working circuits are given.The conduction sequence,the change rule of key protection parameters and the selection method of the transient suppression devices in series and parallel are analyzed.The Pspice equivalent circuit of the transient suppression devices in series is presented The calculation method of the intermediate decoupling inductance of the transient suppressor in parallel operation is given,and the design scheme of the transient protection circuit of the combined protection module of strong electromagnetic pulse is finally determined.In the fourth part,the design method of the combined protection module of the strong electromagnetic pulse is studied.For the protection of the RF link of the front door and the external interconnection cable of the back door of the ultrashort wave radio station,the front stage uses the use of the transient suppression device to quickly limit the strong electromagnetic pulse,and the rear stage adds a filter circuit for the excessive residual current peak value and the waveform oscillation after the front stage limit,and finally completes the strong electromagnetic pulse The design and development of the pulse combination protection module,and the strong electromagnetic pulse injection test and the steady-state insertion loss performance verification.