Bioinspired 4D-Printing Microwave Absorbers With Adaptive Programmable Switches via Morphable Percolation Networks and Resonant Models.

Abstract

The escalating demand for intelligent stealth systems necessitates a paradigm shift from static absorbers to dynamic devices with autonomous and reversible control. Addressing challenges of fixed structure-frequency relationship, we draw direct inspiration from the adaptive coloration of cephalopod skin, which achieves dynamic stealth through reconfiguration of subcutaneous photonic structures. Following this principle, we design a programmable electromagnetic switch via a 4D-printing strategy, which promotes R6M matrix mixed with carbonyl iron directional arrangement. This design enables precise morphological control of absorbers based on a thermally convective temperature gradient by inducing metastable configurations of liquid crystal elastomer. The macroscopically topological reconfiguration and microscopical changes of percolation network both contribute to a dramatic, reversible modulation of electromagnetic characteristics. Consequently, the resonant frequency can precisely convert within X and Ku bands, with the minimum reflection loss enhanced from -30.22 to -61.4 dB and the effective bandwidth enlarged from 8.52 to 11.37 GHz. Notably, this system exhibits excellent cyclic-stability over 100 times, establishing a robust electromagnetic switches. Our work establishes a deterministic mapping between thermal excitation, metastructure geometry, and electromagnetic behaviors, enabling precise and predictable tuning. This paradigm offers inspiration for next-generation electromagnetic protection, with clear potential for integration into adaptive cloaking systems.