Structural‐Functional‐Integrated Ultra‐Wideband Microwave‐Absorbing Composites Based on In Situ‐Grown Graphene Meta‐nanointerface

Abstract Ultra‐wideband microwave absorbing (MA) materials covering the low‐frequency range (2–6 GHz) are highly desirable in civil and military fields. These materials can be fabricated based on the design of electromagnetic meta‐structure. Herein, a structural‐functional‐integrated ultra‐wideband SiO 2 fiber reinforced cyanate ester (CE) MA composite based on an in situ‐grown graphene meta‐nanointerface layer (GrMI) (SiO 2f /GrMI/CE) is reported. The relationship between the periodic structure of the graphene nano‐interface layer and the MA performance is discussed through experiments and simulations. The results show that SiO 2f /GrMI/CE with a thickness of 8.78 mm exhibits an effective absorption bandwidth of 15.46 GHz (2.54–18 GHz). Remarkably, the reflection loss remains basically unchanged upon increasing the incident angle from 5° to 50°. Additionally, GrMI is an effective load‐bearing constituent, which increases the interfacial shear stress between SiO 2f and the CE by ≈210% and contributes to achieving composites with an ultra‐high flexural strength (552.7 MPa). The excellent structural‐functional‐integrated performances ensure that the SiO 2f /GrMI/CE composites are suitable for use as the skin materials of microwave stealth aircraft and other civil facilities. The work provides a novel pathway for the design of thinner, wider, lighter, and stronger MA components.