Design and fabrication of silicon carbides reinforced composite with excellent radar absorption property in X and Ku band

A double layer radar absorbing structure (RAS) with excellent radar absorption property in X and Ku band, has been designed based on the calculated permittivity requirements according to the transmission line theory. The two kinds of SiC fibers with different resistivity reinforced epoxy (SiC_f/epoxy) are chosen and constructed to serve as the lossy layer and matching layer, respectively. The fiber volume fraction of the two layers are specified according to volume fraction dependent dielectric properties of the designed composites, which is determined by the different characteristics of SiC fibers. The thickness dependent absorption property of the double layer SiC_f/epoxy is calculated and investigated. Radar wave absorbing performance of the designed SiC_f/epoxy is measured and the fabricated composite with the total thickness of 4.6 mm shows more than 90% absorption in the whole X and Ku band when the incident angle is less than 30°. Furthermore, the multi-scale radar wave absorption mechanism for the fabricated double layer RAS is discussed based on the multi-scale structure of the fabricated composite.