Ni-plated basalt/BMI origami-core sandwich composites for radar cross-section reduction under high-temperature conditions

This study presents high-temperature origami-core radar-absorbing sandwich composites (ORASC) that provide stable broadband absorption under oblique incidence, aimed at reducing the radar cross-section (RCS) of an engine inlet. The ORASC is fabricated using electroless nickel-plated basalt fiber and bismaleimide (BMI) resin, enabling electromagnetic absorption at temperatures up to 250 °C. Electromagnetic simulations were performed to design the ORASC and evaluate absorption performance as a function of core geometry parameters. At room temperature, the fabricated ORASC maintains absorption performance above 90 % across the f1-f4. Under oblique incidence, the ORASC maintained high absorption performance up to 60° for both VV and HH polarizations. The S-shaped duct with integrated ORASC was analyzed to confirm RCS reduction at the engine inlet. Simulation results indicate that the duct with ORASC reduces RCS over a wide frequency range. By maintaining stable radar-absorbing performance under oblique incidence through multiple scattering, the proposed ORASC demonstrates its potential for use in stealth aircraft engine ducts.