Effect of Aperture Polarization on Lightning Electromagnetic Field Enhancement inside Building Structures at Near and Far Striking Distance

Critical equipment installed in building structures is at exposure risk to a strong electromagnetic field when a lightning strike occurs in its vicinity. In addition to the electromagnetic field profile created by lightning strikes inside structures, the presence of apertures on these structures causes enhancement in the penetrated lightning electromagnetic field. This paper inspects the implications of aperture orientation on the attributes of the penetrated fields inside the building structures, which is not quantified so far. FEKO electromagnetic simulation software is used for modeling and computation, and the structure is considered present at near and far locale to the lightning strike point. The field enhancement is computed due to multiple apertures at parallel and perpendicular polarization to the incident lightning electromagnetic radiation. It is noted that the penetrated electric field distribution profile inside the building is affected by the aperture polarization; at the same time, the magnetic field contour remains unaltered, irrespective of the lightning strike distance.