Bionic Metamaterial Microwave Blackbody with Temperature Insensitivity for C ~ Ku Bands.

Designing microwave absorbers with broadband perfect absorption at high temperatures remains a challenge for researchers due to the variability of material properties with temperature. Herein, inspired by the absorption model of <italic>Papilio blumei</italic>, this work establishes a method to realize broadband metamaterial microwave blackbody using polymer ceramics and bionic metamaterial structures. The size of the high-temperature resistive film and biomimetic hole of the bionic metamaterial microwave absorber (MMA) is optimized based on the trust region framework method. The absorption rate of the MMA reached 99% across the C ~ Ku bands, which breaks the Plank-Rozanov limit by multiple absorption mechanisms (polarization loss, conductive loss, and resonance loss). It is evident from quantitative calculations and power loss density distributions that resonant losses are crucial for microwave energy absorption. Experiment results reveal that the MMA can maintain excellent absorption performance from room temperature to 1000 ℃ which guarantees the potential application for microwave absorber at evaluated temperatures. [ABSTRACT FROM AUTHOR]