Influence of fiber coating on electromagnetic wave absorption properties of SiCf/epoxy composites

• • L-fiber resistivity of ~3 Ω·cm and H-fiber resistivity of ~7×10^5 Ω·cm enable impedance tuning; BN single coating and SiO2/BN dual-coating on L-fibers yield RL < −10 dB across 8.2–18.0 GHz, critical for broadband stealth in X and Ku bands. • • Dual-coating (SiO2/BN) significantly broadens the available thickness range for optimal absorption compared to single BN coating, enhancing design flexibility for load-bearing radar-absorbing structures. • • Stacking sequence of unidirectional prepregs critically influences EWA performance; computational optimization identifies configurations that achieve full-band absorption, reducing trial-and-error in industrial scale-up. • • The introduction of wave-transmitting coatings (BN, SiO2) improves impedance matching and introduces interface polarization, mitigating the inherent impedance mismatch of pure SiC fibers (resistivity 10^1–10^3 Ω·cm) and enabling efficient absorption.