Realization of multi-band microwave absorption and direction-designability in FeSiAl@SiC composite via metastructure-induced interfacial coherent cancellation

Abstract

Radar stealth and electromagnetic pollution concerns jointly drive the advancement of electromagnetic wave-absorbing materials (EWAMs). However, achieving synchronous absorption across widely spaced frequency bands or precisely designing absorption bands at a fixed thickness still poses challenges for EWAMs. To overcome this, we proposed a frequency-targeted absorption strategy combining EWAMs and metamaterials. We first synthesized FeSiAl@SiC composites via ball milling, achieving a reflection loss of −57.12 dB and an effective absorption bandwidth of 6.24 GHz with a thickness of 3.22 mm. Subsequently, we employed a metastructure design (maintaining the overall structure thickness unchanged) for FeSiAl@SiC by replacing the partial absorber with a lossless medium layer containing resonant structures, where interfacial coherent cancellation was induced via electric resonance. This design basically retains the original absorption band while precisely enhancing Ku-band absorption at target frequencies, enabling the metamaterial absorber to achieve >80 % electromagnetic wave-absorbing across 5.6–15.61 GHz. It also improves the Radar Cross Section reduction performance at the complementary absorption frequency points. This study presents a hybrid design strategy for EWAMs and metamaterials, offering an effective approach to achieve multi-band and broadband absorption for applications in radar stealth, electromagnetic compatibility, and modern communication systems.