A multilayered microwave absorbing composite structure enhanced by fiberglass enforced epoxy laminate array

A multilayered composite structure with ultra-wideband and strong microwave absorbing performance has been developed, which is prepared through vacuum bag molding process, and the fiberglass enforced epoxy laminate (FEPL) array on its surface is fabricated by computer numerical control (CNC) carving method. The surface density of the whole composite structure with FEPL array is about 2.4 kg/m², and the thickness is about 10.0 mm. Both simulation and measurement results confirm that FEPL array can considerably improve stability of the incidence angle, increase absorptivity, and broaden the absorption bandwidth. The FEPL array enhances the oblique incidence performance of the composite structure ranging from 40° to 60°, while simultaneously expanding the fractional bandwidth (FBW) by approximately 9.1%. Moreover, it achieves a notable reduction in the average reflection coefficient at normal incidence, decreasing it by about 11.3 dB from −14.4 dB to − 25.7 dB. High performance and simple preparation processes for composite structure indicate that it is suitable for practical engineering applications.