3D printed PyC/Al2O3 ceramic metamaterials with different micro-channels for tunable microwave absorption

The PyC/Al2O3 ceramics with micro-channels were prepared by the 3D printing, which realized the tailored microwave absorption properties via designing meta-structures with diverse micro-channels to tailor the permittivity of the ceramic. The permittivity of the ceramics can be effectively controlled by micro-channels with different orientations and sizes, which could be particular for designing multi-layer impedance matching metastructures with different dielectric properties. The absorption bandwidth of PyC/Al2O3 ceramics is effectively expanded, which realized great than 90 % EM wave absorption in the frequency range of 6-18 GHz, indicating an efficient absorption band of 12 GHz. Therefore, this study put forward a new strategy to tailor the permittivity of 3D printed ceramics by introducing micro-channels with sizes of sub-wavelength, which could enlarge the design freedoms for 3D printed microwave absorbing ceramics.