3D printed bioinspired chiral helical-vortex metastructures for broadband electromagnetic wave absorption

Conventional structural electromagnetic (EM) wave absorbers rely on inherent material losses and gradient design to optimize absorption performance. However, they inevitably face a fundamental trade-off between broadening the effective absorption bandwidth and achieving lightweight configurations. Inspired by the helical phyllotaxis of plants, a growth mechanism that maximizes light capture efficiency, this work proposes a bioinspired chiral helical-vortex metastructure featuring a graded solid fraction, continuously expanding helical laminae, and intrinsic chirality, which achieves impedance matching and broadband absorption through multiple internal reflections, prolonged EM propagation paths and polarization conversion. By combining a dielectric loss composite with rational structure, this multiscale optimization strategy enables broadband absorption with the reflection loss RL ≤ −10 dB covering 5.2–18 GHz, while exhibiting outstanding angular insensitivity at incidence angles of up to 45° and polarization insensitivity. This work demonstrates the great potential of bioinspired chiral structures for EM absorption, providing a promising design strategy for thin, broadband absorption metastructures with angular insensitivity and polarization insensitivity.