Study On The Coupling Response Of Strong Electromagnetic Pulse To Transmission Cable

With the continuous development of the digital age,an increasing number of high-tech electronic devices are being used in information warfare.The normal operation of electronic devices depends on transmission lines,which can generate large induced currents under strong electromagnetic pulses.This can affect the normal operation of electronic devices,and in serious cases,cause damage.Therefore,various countries have conducted a series of research on the use of nuclear technology to generate strong electromagnetic pulses and use in actual combat.As a result,electromagnetic protection for transmission lines has become particularly important.This thesis studies the electromagnetic coupling effects of different targets such as cable in the unmanned aerial vehicle cabin,double-layer buried cable,and enclosures with complex apertures.The main research contents are as follows:(1)Aiming to the problem of diverse wiring methods and complex cable types inside the UAV cabin,this thesis used the CST software to study the coupling response of strong electromagnetic pulses to cables in a certain type of unmanned reconnaissance aircraft.The internal structure of the UAV and the wiring method were simulated for modeling,and the influence of different wiring methods and cable types on coupling response in the UAV cabin was analyzed.The results showed that when the strong electromagnetic pulse is being fired at the head of the UAV,the induced current on the cables in the front section of the cabin was larger when the direction of the cable arrangement was parallel to the incident direction or the magnetic field polarization direction.The induced current was highest on the cables parallel to the electric field polarization direction,and the induced current was lowest on the shielded twisted pair cable.(2)Aiming to the low efficiency of the full-wave algorithm to calculate the distribution of the transmission electric field under a double layer of soil,this thesis derives an analytical expression for the distribution of the transmitted electric field under the double-layer soil based on the theory of transmission of plane waves in the medium.Using this analytical expression has higher computational efficiency in calculating the distribution of transmission electric fields.On this basis,combined with the transmission line equation and Green’s function,the induced current on the transmission line is calculated.The influence of the thickness,humidity,dielectric constant of the upper medium,and the depth of wiring on the coupling effect of buried cables are studied.The results show that the thickness of the upper medium has a small effect on the induced current of the cable,but the humidity,dielectric constant of the upper medium,and the depth of wiring have a significant effect on the induced current of the cable.The analytical algorithm is compared with the full-wave simulation software CST,and the good accuracy of the algorithm is verified.(3)Aiming at the problem of low efficiency of the full-wave algorithm to calculate the shielding effectiveness of complex open cavities.This thesis proposes an expression for the impedance of complex apertures based on the Bethe aperture theory.Combined with Yin’s cavity equivalent circuit model,analytical modeling of three types of complex aperture cavities,including circular,elliptical,and circular slot shapes,is conducted to calculate the shielding effectiveness of the three complex aperture cavities.This analytical model can consider the effects of aperture shape,aperture array number,and distance between observation point and aperture on shielding effectiveness,and analyze the impact of different parameters on the shielding effectiveness of the aperture cavity models.The results show that,for the same aperture area,the shielding effectiveness of the circular slot-shaped aperture cavity is better than that of the circular and elliptical aperture cavities.The shielding effectiveness of the aperture cavity increases with an increase in the number of aperture arrays,and it gradually increases as the distance between the observation point and the aperture increases.The analytical algorithm is compared with the full-wave simulation software CST,and the good accuracy of the algorithm is verified.