Mechanism-oriented design of lightweight porous metamaterial absorbers enabled by Co3Fe7/C nanofibers for broadband and angle-insensitive microwave attenuation

The increasing complexity of electromagnetic environments demands lightweight, broadband, and angle-insensitive electromagnetic wave absorbers. However, achieving a synergistic balance between impedance matching and attenuation capability remains a critical challenge. Herein, we propose a mechanism-oriented design strategy for a lightweight porous metamaterial absorber based on Co₃Fe₇/C nanofibers. By combining dielectric-magnetic material optimization with porous structural engineering, impedance matching and energy dissipation are simultaneously regulated. Simulations show that thickness, pore radius, and porosity critically determine electromagnetic responses. The optimized absorber achieves an effective absorption bandwidth of 6.1 GHz (8.2–14.3 GHz) and a minimum reflection loss of −56.86 dB at 2.5 mm thickness, with robust angle-insensitive performance up to 60°. Mechanistic analysis attributes the superior performance to synergistic coupling of multiple scattering, interfacial polarization, conduction loss, magnetic resonance, and optimized impedance matching. This work provides a universal framework integrating material design with structural engineering for next-generation lightweight electromagnetic wave absorbers.