Pneumatic Structural Deformation to Enhance Resonance Behavior for Broadband and Adaptive Radar Stealth

Ideal radar absorbing materials (RAMs) require instantaneous, programmable, and spontaneous adaptability to cope with a complex electromagnetic (EM) environment across the full working frequency. Despite various material systems and adaptive mechanisms having been demonstrated, it remains a formidable challenge to integrate these benefits simultaneously. Here, we present a pneumatic matrix that couples morphable MXene/elastomer conductors with dielectric spacers, which leverages controllable airflow to reconfigure the spatial structure between a flat sheet and a hemispherical crown while maintaining resistance stability via wrinkle folding and unfolding. The interdimensional reconfigurations drastically induce multiple resonance behavior, enabling the matrix remarkable frequency tunability (144.5%), ultrawide bandwidth (15 GHz), weak angular dependence (45 degrees incidence), ultrafast responsiveness (similar to 30 ms), and excellent reproducibility (1000 cycles). With multichannel fluidic and conceptual automated control systems, the final pneumatic device demonstrates a multiplexed, programmable, and autonomous transformable mode that builds a promising platform for smart radar cloaking.