What it is
Researchers 4D-printed a pyramidal metamaterial from a hierarchically porous, carbon-supported high-entropy ceramic bonded to a shape-memory elastomer, combining macroscopic cavity resonances with microscopic defect-induced polarization. The structure achieves an absorption bandwidth of 14.16 GHz at 90% or greater absorption, a 98.88% improvement over the same material in bulk form. A moderate 120°C thermal stimulus triggers spatial reconfiguration, shifting tunable absorption across the 5.24 to 18 GHz range while holding reflection loss below -20 dB (99% or greater absorption). The base material was formed into helical, origami-inspired, and load-bearing geometries.
Why it matters
Conventional microwave absorbers are locked to a fixed geometry and a narrow band once fabricated, so they cannot follow a changing threat or channel. Coupling a high-entropy ceramic absorber to a shape-memory matrix lets one physical part change its own shape, and therefore its absorption band, on demand, addressing the reconfigurability gap in adaptive radar and wireless stealth.
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Filed undermetamaterials, microwave absorption, 4d printing, high-entropy ceramics, shape memory