The so far developed microwave absorbers all exhibit dramatically changing absorption with temperature, hindering them from working in a broad temperature range. Here, a refractory metamaterial microwave absorber (rfMMA) with the absorption insensitive to temperature by using refractory ceramics of conductive titanium diboride (TiB₂) as unit cells and dielectric alumina (Al₂O₃) as a spacer is designed and experimentally demonstrated. The as‐proposed rfMMA shows strong microwave absorption in a wide temperature range. A definite physical equivalent circuit model that tightly links the structural and constitutive parameters of the rfMMA to its absorption properties is established. It reveals that with a stable configuration of the as‐proposed rfMMA, the little temperature effect on the permittivity of Al₂O₃ spacer and the big enough conductivity of TiB₂ unit cells ensure an almost constant absorption in a wide temperature range, avoiding the temperature‐sensitive problem of traditional refractory absorbers. Moreover, the excellent chemical stability of TiB₂ and Al₂O₃ at high temperature further ensures the long‐term service of the as‐fabricated rfMMA, as confirmed by experiments. This work provides a route to achieve refractory microwave absorbers with strong absorption at a wide temperature range, and illustrates a bright prospect of the all‐ceramic metamaterial absorbers in high temperature applications.

中文翻译：

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对温度不敏感的具有强吸收性的耐火材料超材料微波吸收器

迄今开发的微波吸收器均显示出随温度急剧变化的吸收，从而阻碍了它们在较宽的温度范围内工作。此处，通过使用导电性二硼化钛（TiB ₂）的耐火陶瓷作为单位晶胞和介电氧化铝（Al ₂ O ₃），具有对温度不敏感的吸收的耐火超材料微波吸收剂（rfMMA））作为隔离片的设计和实验证明。提议的rfMMA在很宽的温度范围内显示出很强的微波吸收能力。建立了确定的物理等效电路模型，该模型将rfMMA的结构和构成参数与其吸收特性紧密联系在一起。结果表明，通过稳定配置的rfMMA，温度对Al ₂ O ₃间隔物的介电常数的影响很小，而TiB ₂晶胞的电导率足够大，从而确保了在宽温度范围内几乎恒定的吸收，从而避免了传统耐火吸收剂的温度敏感问题。此外，TiB ₂和Al ₂ O ₃的优异化学稳定性实验证明，在高温下进一步确保制成的rfMMA的长期使用寿命。这项工作提供了在宽温度范围内获得具有强吸收性的耐火微波吸收剂的途径，并说明了在高温应用中全陶瓷超材料吸收剂的光明前景。