Research On Electromagnetic Pulse Coupling Into A Narrow Slot

High-altitude nuclear explosion can produce high-intensity electromagnetic pulse.Electromagnetic pulse coupled into the aircraft around the detonation point by the “front door” and the “back door” which will damage the electronic equipment and circuit system. Electromagnetic pulse pose a serious threat to the normal operation of aircraft through the coupling of slots. Research on electromagnetic pulse coupling into the cavity with a narrow slot in order to provide the theoretical basis for the protection of "back door" couplingFirst, based on the finite integral method(FIT), an aircraft model have been established. Selecting slots with dimension of several millimeters as research object, analyse the coupling effects by the different cavity size, shield shapes, incident angles, different shapes with the same area, the slot combinations. It is found the strong resonance at the slot, the energy coupling into the cavity not only decided by the dimension of the slot, but also the size and shape of the cavity.Second, this paper derived square slot multi-peak resonant frequency formula by the antenna complementary principle. It is found that a square slot multi-peak resonant frequency point not only depends on the dimensions of the slot but also the quantity of it, and the theory expression results matches the simulation results well with relative deviation below 5%.Third, investigation the coupling effects of the nested cavities with internal and external slots about the relative position. When the incident Angle θ=0o, this paper analyses coupling function about parallel distribution and vertical distribution of the slots. It is found that electromagnetic energy coupling into the cavity, the second resonance effect is founded of the parallel distribution slots at the point of the internal slot. At the same time, the peak electric field only a few volts per meter at the point of the internal slot of the vertical distribution slots. So this distribution can effectively reduce the interference of electromagnetic pulse to electronic devices.