Shielding Performance of Materials Under the Excitation of High-Intensity Transient Electromagnetic Pulse

Shielding effectiveness (SE) dominates the shielding performance of materials. Under the excitation of high-intensity transient electromagnetic pulse, especially the wide-band transient electromagnetic pulse, how to characterize and calculate the SE of shielding materials is not clear. In order to reveal the shielding performance of materials towards the wide-band transient electromagnetic pulse, a systematic experimental investigation was performed on a home-made SE measurement system. The `peak value reduction ( SE
_PR
)' is verified to be an effective approach for the characterization of SE of shielding materials. The SE of the employed materials shows no noticeable change even with the excitation field intensity increasing to 200 kV/m, which is significantly different from that of high-power microwave (HPM). Under the excitation of HPM, the SE of materials starts to increase at a field intensity of 19.4 kV/m and becomes saturated at 33.6 kV/m. Further analysis discloses that the variation of SE of materials is mainly dependent on two factors, one is the intrinsic property of the material itself, and the other is energy density spectrum of the excitation high-intensity transient electromagnetic pulse. The energy in per frequency unit (10 MHz) for wide-band transient electromagnetic pulse is far lower than that of HPM, resulting in an evident dissimilarity in the changes of SEs of shielding materials.