Abstract: The development of high-performance microwave absorbing materials (MAMs) with broadband operation and temperature-responsive adaptability marks a significant advancement in electromagnetic protection and stealth technologies. Achieving simultaneous broadband absorption and intelligent responsiveness poses challenges in dielectric loss optimization through material selection and structural engineering. This study presents an innovative solution via subwavelength architecture design. We employ a facile electrospray strategy to fabricate reduced graphene oxide microspheres (rGOms) with tunable dimensions, where structural and compositional design further improve microwave absorption. The scale of rGOms correlates with interfacial dipole scales in macroscopic statistics, and their multiscale design results in a broader dielectric relaxation distribution. This synergistically enhances the effective absorption bandwidth (EAB). Furthermore, the discontinuous design of subwavelength units effectively extends the transmission path of electromagnetic waves, leading to additional multiple reflections and scattering within the system. At an equal mass ratio of 700 and 300 µm rGOms, the EAB of rGOms/epoxy (EP) composites reaches 7.2 GHz. Moreover, leveraging dynamic interfacial polarization provided by thermally responsive vanadium dioxide (VO₂), the rGOms/VO₂/EP composite demonstrates a dynamic adjustment capability that shifts the EAB by 2.6 GHz. This study may serve as a valuable reference for designing intelligent MAMs with broad attenuation frequency ranges based on multi-interface engineering.

Key words: Multi-scale, Interface engineering, Intelligent, Microwave absorption, Wideband absorption