Bioinspired 3D printed metamaterial for wideband microwave absorption and aerodynamic efficiency

To further decrease the mass and thickness of multifunctional wideband microwave absorption metamaterials (MAMs), this study applies photonic crystal principles to the field of microwave absorption. Drawing inspiration from the structural coloration regulation of Morpho Menelaus scales, a novel integrated bioinspired MAM named MM is designed. MM possesses low drag coefficient, hydrophobicity, mechanical load-bearing capacity, and wideband radar stealth functionality. Utilizing PA6@CF filaments and material extrusion 3D printing technology, mechanical test specimens and MM specimens optimized through particle swarm optimization (PSO) are rapidly fabricated at low cost. Reflectivity tests at normal incidence reveal that MM (with a thickness of 8 mm) achieves an effective absorption bandwidth (EAB) of 33.4 GHz within the 2–40 GHz frequency range. Under transverse magnetic polarization and 60° oblique incidence conditions, MM demonstrates a coverage rate of 98.5 % for EAB. Furthermore, three-point bending tests demonstrate MM's excellent deformation capabilities (up to 50 mm) and mechanical load-bearing performance (bending strength reaching 78 MPa), laying the groundwork for its application on complex surfaces. Lastly, targeting the application of microwave absorption metamaterials on high-speed moving objects, comparative analysis of MM and five typical MAMs reveals that MM exhibits the lowest drag coefficient (C_d = 0.132). In summary, this study offers a straightforward and replicable method for designing, optimizing, fabricating, and evaluating MAMs, while suggesting aerodynamic performance as a novel metric for assessing their multifunctional capabilities.