Effects of a damaged composite face to the electromagnetic wave transmission characteristics of low-observable radomes

E-glass/epoxy composites and aramid/epoxy composites are suitable materials for EM (electromagnetic) transmission systems because they have low dielectric constants, particularly good for the construction of radomes. The low-observable radome not only selectively transmits the EM wave to antenna systems, but also protects the internal antenna system from external impacts. In this work, the radome specimens were made of sandwich constructions composed of composite faces such as E-glass/epoxy composite and aramid/epoxy composite, foam core and an FSS (frequency selective surface). Because the damage to the radomes by external impact load may affect the EM wave transmission characteristics, the EM wave transmission characteristics of various radome specimens were measured using the free space measurement method with respect to impact magnitude. Additionally, the damage characteristics of the radome specimens were observed with respect to the face composite material of the sandwich constructions.