High‐efficiency design of multifunctional radar absorbing honeycomb structures for enhanced ultrathin, broadband, and load‐bearing performance

Abstract With the rapid advancements in anti‐stealth technology and electronic reliability, radar absorbing structures urgently need to achieve electromagnetic‐mechanical enhancement. However, the drawback of the current frequency selective surface (FSS) film still affects the interfacial strength of the structures, limiting the improvement of the mechanical performance. This work proposed an ultrathin, broadband, and load‐bearing integrated radar absorbing honeycomb structure (RAHS), fabricated via a high‐efficiency multi‐manufacturing approach, replacing the traditional FSS film. The result reveals that optimizing the structural geometry and resistance of the interlocked functional honeycomb (F‐HC), FSS‐laminate, and polylactic acid honeycomb lattice cores, the optimal RAHS can achieve an excellent absorption bandwidth of 35.30 GHz (absorptivity>87%) under TE polarization at a thickness of only 9 mm with a density of 0.55 kg m⁻³ as well as possess outstanding compressive strength of 21.9 MPa and energy absorption of 6.43 MJ m⁻³, increasing of 200% compared with RASH (without lattice cores). Notably, the proposed electromagnetic mechanism demonstrates that the electromagnetic synergistic effects originate from the electromagnetic loss capabilities of F‐HC and the L‐C resonance and resistance between the square loop and square patch, and the gradient impedance matching between FSS‐laminate and F‐HC with lattice cores. The multi‐stage effect between the interlocked square F‐HC structure and the hexagonal honeycomb lattice cores significantly enhances the energy absorption performance. This work provides a high‐efficiency pathway for achieving high‐performance electromagnetic functional structures. Highlights RAHS is designed for ultrathin, broadband, and load‐bearing integration. The multi‐manufacturing approach of RAHS effectively resolved the drawbacks of the current FSS film. Filling lattice cores enhanced compressive strength by 200%, and energy absorption by 793%. The multi‐stage effect between the F‐HC and lattice cores enhanced the mechanical performance of RAHS. Electromagnetic synergy improved broadband of RAHS via FSS‐laminate and lattice cores.