Microwave-infrared compatible stealth via high-temperature frequency selective surface upon Al2O3-TiC coating

Abstract

Microwave-infrared compatible stealth is always challenging due to the difficulty in reducing the microwave reflection and infrared emission simultaneously. In this work, we designed and prepared an ultra-thin microwave-infrared bi-stealth coating composed of Al 2 O 3 -TiC absorbing coating and high-temperature frequency selective surface (FSS). The structure, microwave absorption property, infrared stealth ability and their compatibility were investigated. The results show that the introduction of high-temperature FSS composed of alloy clearly improved the impedance matching within the different layers and decreased the thickness of the composite coating as low as 0.95 mm. In the frequency range of 2–18 GHz, the effective absorption bandwidth of the reflection loss less than − 5 dB is 6.11 GHz at room temperature (RT). The − 5 dB absorption bandwidth can be maintained of about 5.34 GHz at 600 ℃. A low infrared emissivity was obtained in the wavelength range of 2–22 µm due to the alloy-made FSS. The well bi-stealth performance over wide temperature ranges is attributed to the compatible structural design and specific preparation process, which is promising for practical applications. • An “ultra-thin” microwave-infrared bi-stealth coating was designed and prepared. • The coating has good high-temperature infrared-radar bi-stealth performance over RT~600 ℃ wide temperature range. • The reflection loss of the coating is below − 5 dB in the x-band. Meanwhile, it has a lower infrared emissivity.