Multi-Scale Dispersion Engineering on Biomass-Derived Materials for Ultra-Wideband and Wide-Angle Microwave Absorption.

Efficient electromagnetic waves (EMWs) absorbing materials play a vital role in the electronic era. In traditional research on microwave absorbing (MA) materials, the synergistic modulation of material dispersion and structural dispersion of EMWs by incorporating multi-scale effects has frequently been overlooked, resulting in an untapped absorption potential. In this study, the material dispersion customization method based on biomass carbon is determined by quantitative analysis. The study carries out thermodynamic modulation of carbon skeleton, micro-nano porous engineering, and phosphorus atom donor doping in turn. The dielectric properties are improved step by step. In terms of structural dispersion design, inspired by the theory of antenna reciprocity, a Vivaldi antenna-like absorber is innovatively proposed. With the effective combination of material dispersion and structural dispersion engineering by 3D printing technology, the ultra-wideband absorption of 36.8 GHz and the angular stability of close to 60 ° under dual polarization are successfully realized. The work breaks the deadlock of mutual constraints between wave impedance and attenuation rate through the dispersion modulation methods on multiple scales, unlocking the potential for designing next-generation broadband wide-angle absorbers.