Multi-objective optimal design for flexible bio-inspired meta-structure with ultra-broadband microwave absorption and thin thickness

There is an urgent need for the application of broadband Microwave Absorption (MA) structures on the leading edges of aircraft wings, which requires the MA structures to possess both the broadband MA performance and great surface conformability. To meet these requirements, we designed and fabricated a flexible bioinspired meta-structure with ultra-broadband MA, thin thickness and excellent surface conformality. The carbonyl iron powder-carbon nanotubes-polydimethylsiloxane composite was synthesized by physical blending method for fabricating the MA meta-structure. Through geometry-electromagnetic optimal design by heuristic optimization algorithm, the meta-structure mimicking to the nipple photonic nanostructures on the eyes of moth can achieve ultra-broadband MA performance of 35.14 GHz MA bandwidth (reflection loss ≤ –10 dB), covering 4.86–40.00 GHz, with thickness of only 4.3 mm. Through simple fabrication processes, the meta-structure has been successfully fabricated and bonded on wings’ leading edges, exhibiting excellent surface conformability. Furthermore, the designed flexible MA meta-structure possesses significant Radar Cross-Section (RCS) reduction capability, as demonstrated by the RCS analysis of an unmanned aerial vehicle. This flexible ultra-broadband MA meta-structure provides an outstanding candidate to meet the radar stealth requirement of variable curvature structures on aircraft.