Achieving good infrared-radar compatible stealth property on metamaterial-based absorber by controlling the floating rate of Al type infrared coating

In order to realize the infrared stealth ability for the metamaterial-based EM absorbers, the polyurethane(PU)/aluminum (Al) composite coating with low infrared emissivity is successfully applied on its surface. The influences of the floating rate of Al particles on the infrared emissivity and their compatibility feature with metamaterial-based EM absorbers have been systematically investigated. Infrared emissivity values are measured using IR-2 Infrared Emissometer in the wavelength range of 8–14 μm and the electromagnetic wave absorption properties of the metamaterial-based EM absorbers with or without infrared coatings are measured by the arch method. When the content and floating rate of Al powders are 20% and the 90%, respectively, the metamaterial-based EM absorber with infrared Al/PU coating displays not only a lower emissivity but also good electromagnetic wave absorbing properties which means the good infrared-radar compatibility condition can be achieved. The results indicate that, after coating with this PU/Al infrared layer, the infrared emissivity of metamaterial absorbers can be greatly lowered from 0.65 to below 0.204 and meanwhile its good radar absorbing performance can still be maintained without much reduction.