Design and Optimization of Microwave‐Absorbing Structures With Carbonyl Iron Powder–Functionalized Continuous Carbon Fiber Grids Embedded in Continuous Glass Fiber‐Reinforced Composites

Introducing periodic structures into GFRP is a key approach to integrating structural and microwave‐absorbing functions. However, conventional metallic periodic structures often cause stress concentration problems. In this study, periodic CIP/CF grid structures were embedded into GFRP laminates, which were made from CIP‐modified continuous CF tapes. This design uses epoxy resin for integral molding of continuous GFs and CFs, which can effectively prevent interfacial stress concentration and maintain the excellent mechanical properties of GFRP laminates. Critical geometric parameters, including the CIP/CF grid bandwidth and GFRP layer thickness, were optimized using the genetic algorithm in MATLAB. The optimized structure was then modeled, and its microwave absorption performance was verified using HFSS software. Experimental results confirmed the HFSS simulation data, showing effective absorption in the 6.3–8.8 and 10.3–18 GHz frequency bands, with a peak absorption of −33.8 dB. Additionally, the microwave‐absorbing laminate with periodic CIP/CF grid retained the inherent high specific strength of GFRP and exhibited improved flexural strength, reaching 470 MPa (a 7% improvement over neat GFRP). The combined electromagnetic properties of GFRP, CF, and CIP, along with the synergistic effect of the CIP/CF grids, enabled the ultimate laminate to achieve broadband microwave absorption performance.