Biomimetic binary interface engineering for ultra-light tunable low-frequency electromagnetic absorbers

Urgently, low-frequency (C-X band) electromagnetic absorption has emerged research hotspot along with 5G communication advancements and escalating military stealth demands. Single optimization strategies for cross-band systems face significant challenges. Particularly, the dispersion characteristics of dielectric constants exhibit marked variations across bands. Inspired by the skin’s "dermal-epidermal" thermoregulation system, we designed a "dermal-epidermal" binary interface to synergistically regulate cross-band electromagnetic impedance matching. Typically, "Dermis" interface polarization can effectively tune C-band impedance. And "Epidermis" designed plasmonics effectively tune X-band absorption intensity. By leveraging such binary synergy, the "dermal-epidermal" configuration achieved full X-band coverage and 2.48 GHz at the C-band (1.60 wt.%). And plasmonic-induced exchange resonance exhibits a distinct resonance peak in the X-band. This resonance peak plays a crucial role in reducing reflection loss (RL) and in increasing the effective absorption bandwidth (EAB). This work establishes a novel biomimetic configuration for lightweight, tunable low-frequency absorbers, advancing broadband electromagnetic material design.