Efficient S-band electromagnetic wave absorption in hierarchically hollow CoFe2O4/C nanocomposites modified with ZIF-67 derivatives

Abstract

Designing electromagnetic wave-absorbing materials (EWAM) with high-efficiency absorption in the S-band (2–4 GHz) is crucial for applications like radar systems, satellite communications, and wireless technologies. However, achieving such absorbing materials in the S-band region has been less explored. The key challenges include complex multi-phase structures, the need for a precise balance between magnetic and dielectric properties, and achieving effective impedance matching. This study presents a multi-level hollow structure EWAM enabling efficient S-band absorption. Specifically, the hierarchical hollow CoFe₂O₄/Co/C (CFCC-500) material achieved a minimum reflection loss (RL_min) of −53.7 dB at 3.57 GHz with a thickness of 3.6 mm. The CFCC-500 features an innovative design of a multi-level hollow structure where small hollow structures are embedded within a larger hollow sphere-based framework. The strong absorption performance is attributed to the balance between dielectric and magnetic losses, which work synergistically to dissipate electromagnetic energy. Moreover, optimized impedance matching ensures efficient energy absorption, minimizing reflection and maximizing dissipation. This research provides valuable insights into optimizing EWAM performance through nano-structural engineering, offering highly efficient absorbers for critical low-frequency applications.