• SiC@RGO porous films were fabricated via two-step reduction (HI chemical and solid-phase microwave), achieving thickness increase from ~20 to 200 μm due to gas release during 3 s microwave irradiation.
• The optimal GO/SiC mass ratio of 4:1 yielded a total shielding effectiveness (SET) of 35.6 dB with a low reflection SE (SER) of 2.8 dB, indicating absorption-dominated shielding.
• SiC whiskers enhance multi-reflection, interfacial polarization, and dielectric attenuation of electromagnetic waves, critical for EMI absorption.
• Multilayer films combining SiC@RGO porous films and MWCNT buckypapers achieved a high SET of 75.1 dB with SER of only 2.7 dB at ~1.5 mm thickness, suitable for packaging or lining applications.