| The development of IT-based warfare and electromagnetic weapons has resulted in increasingly complex electromagnetic environment of battlefield.This paper took an electromechanical fuse as the object of study,the influence of electric field inside the fuse and the coupling laws of micro strip line on the PCB to electromagnetic energy are studied by numerical simulation.The anti-interference capabilities of the fuse before and after electromagnetic protection are comparative analyzed by simulation.The damage of executive circuit inside the shell of fuse under the irradiation of high-frequency and strongly electric field were researched by experiment.The specific content of the work is as follows:Based on one electromechanical fuse,the working principle was analyzed,and the simplified model of shell and PCB was built.The simulation software CST was applied to simulate the effects of the aperture,penetrating wire,coil and different waveforms of electromagnetic pulse on shielding effectiveness of the shell of fuse,and the change rules of induced current on micro strip line was obtained.The simulation results show that the aperture is an important reason for electromagnetic leakage of shell,penetrating wire and coil lead the shielding effectiveness of the shell drop sharply.Among UWB,NEMP and LEMP,UWB with more high-frequency energy is more likely to cause interference to the fuse studied in this paper.The coupling current of micro strip line increases with increasing length and width,and the change of width will affect the transmission characteristics of high-frequency current,while increasing the included angle of micro strip line will reduce the induced current.The anti-interference performance of the fuse before and after electromagnetic protection was compared and analyzed by simulation software,the inhibition of absorbing materials on the resonance of cavity of the fuse was analyzed,and the best installed position of absorbing material is the top cover of fuse.Parameter sweep was used to get the best thickness of aperture of the fuse studied in this paper,and the restraint of interaction between micro strip line and electromagnetic interference by the shield of circuit was researched.The SPICE model of true electronics is simulated,to analyze the effect of filter and TVS on EMP.The radiation experiment of sweeping-frequency and strongly electric field on the simulating fuse before and after protection was carried out,the number of frequencies occurring wrong operation was compared,to verify the effectiveness of the electromagnetic protection.It can be seen from the experimental result that the frequencies of misoperation of executive circuit inside the fuse with aperture are close to resonant frequency,and there is no misoperation when the size of aperture is small.The number of frequencies of misoperation increased obviously when the penetrating wire is added,but the simulating fuse with coil was all malfunctioning,which indicated that the coupling ability of the coil to the high-frequency electromagnetic energy was weak than penetrating wire.After installing the absorbing material and shielding cover of circuit in the simulating fuse with penetrating wire,the number of frequencies of misoperation is reduced,which verifies the effectiveness of these two electromagnetic protections. |
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