TY  - JOUR
AU  - Qiao, Mengke
AU  - Li, Xiangcheng
AU  - Chen, Pingan
AU  - Zhu, Yingli
AU  - Chen, Fu
AU  - Wu, Jiang
AU  - Luo, Gangtao
TI  - SiBCN/FeSiAl composite torsion gradient cavity metamaterial enables microwave absorption at elevated temperature
JO  - Microstructures
PY  - 2026
VL  - 6
IS  - 5
SP  - 
EP  - 20260113
SN  - ISSN 2770-2995 (Online)
AB  - <p>In high-temperature, broadband microwave stealth applications, conventional absorbing materials fail to reconcile thermal stability with strong absorption and wide-spectrum microwave dissipation. To overcome the challenge, this study proposes and validates high-temperature-resistant torsion gradient cavity metamaterial absorbers composed of a SiBCN ceramic matrix and flake-shaped FeSiAl. The torsion gradient cavity structure induces four electromagnetic resonances within the 2~18 GHz range, enabling the real part of the effective complex permittivity (<i>ε</i>'<sub>eff</sub>) to be broadly tuned from -3.2 to 88 and that of the equivalent complex permeability (<i>μ</i>'<sub>eff</sub>) from -53.7 to 34.0. Meanwhile, the imaginary part of the permeability (<i>μ</i>"<sub>eff</sub>) is substantially elevated from near zero in the pristine dielectric medium to a range of 1.8~92.2. These characteristics activate multiple synergistic microwave loss mechanisms, achieving simulated full-band absorption coverage across 2~18 GHz, while the measured effective absorption bandwidth is 2.4~18 GHz at room temperature and 3.0~18 GHz at 800 °C, with the minimum reflection loss (<i>RL</i><sub>min</sub>) values below -20 dB at all temperatures. Thereby realizing the synergistic optimization of high-temperature tolerance and broadband, high-efficiency microwave absorption. The experimental results are in good agreement with simulations, enriching the design methodology and technological implementation pathways for microwave-absorbing materials deployed in high-temperature extreme environments.</p>
KW  - High-temperature resistance
KW  - metamaterial
KW  - torsion
KW  - gradient
KW  - cavity
DO  - 10.20517/microstructures.2026.119
UR  - https://dx.doi.org/10.20517/microstructures.2026.119