Research On The Coupling Characteristics Of Electromagnetic Pulse In Electronic Equipment

With the development of electromagnetic interference in complex environment,it is urgent to study the coupling effect of electronic devices in complex electromagnetic environment.Nuclear electromagnetic pulses from high-altitude nuclear explosions can be easily coupled to the chassis via antennas,holes and cables on electronic devices,affecting electronic components.In this paper,we first select CST electromagnetic simulation software based on the time domain limited integral method(FIT),establish the physical model of the electronic equipment chassis,and study the coupling law of the inside of the chassis under the irradiation of the high-altitude nuclear electromagnetic pulse and the effect of the shape and size of the chassis on the strong harmonious vibration position of the coupling field in the cavity.Then,the coupling characteristic simulation study is carried out for the two main coupling channels,the hole seam and the cable in the electronic equipment chassis.Finally,on the basis of the definition of electric field coupling function,the comparison coefficient of hole seam and cable coupling is introduced,the simulation analysis is carried out in the three cases of the shielding cavity body having only the hole seam,only the cable and the hole seam and cable at the same time,and the pulse simulation test is carried out on the metal shielding cavity with the hole seam and cable using the transmission line type bounded wave electromagnetic pulse simulation system,which verifies the accuracy of the simulation results.The results of the study show that:(1)When the high-altitude nuclear electromagnetic pulse enters the shielding cavity through the hole seam coupling channel,the center axis of the hole seam is the largest coupling field than in other positions.Electromagnetic waves in the vicinity of the hole to produce a strong coupling field enhancement,cavity resonant phenomenon occurred near the center of the cavity,and the back wall of the cavity body has a reflective effect on it,while shielding the shape and size of the cavity not only affect the internal coupling field strong small but also cause the offset of the internal resonant point.(2)When the high-altitude nuclear electromagnetic pulse enters the shielding cavity through the square hole seam coupling channel,the hole seam is set in the positive center of the cavity,the internal coupling field is the largest,the more off the center of the internal coupling of the field is smaller;The longer the edge of the rectangular hole seam perpendicular to the polarizing direction of the electric field,the stronger the field of coupling in the cavity,and also causes a certain offset of resonance points in the cavity,and the circular hole seam is the least strong coupling field than in the rectangular and square hole seam cavity The smaller the hole seam area,the less energy is coupled into the cavity;the thickness of the hole seam not only affects the strong and small coupling field in the shielding cavity,but also shifts the resonance point in the cavity,showing the tendency to increase the resonance point to the right with the thickness;and the honeycomb hole seam array is less intense when the coupling field is strong in the cavity.(3)When the high-altitude nuclear electromagnetic pulse enters the shielding cavity through the cable hole seam coupling channel,the cable will be coupled to the induction voltage or current,wherein the twisted pair coupling voltage is the highest,the single-line second,the smallest on the coaxial line;When the shielding cavity body contains a through-cable,the length change of the extra-cavity cable in the cavity affects the strong coupling field at the center of the shield cavity body,and all show the longer the length,the greater the energy of the coupling into the cavity.However,the change of cable length outside the cavity has no effect on the position of the cavity resonant point,and the change of cable length in the cavity causes the position of the cavity resonant point to be regularly offset.