A research team led by Prof. Jian Lu from City University of Hong Kong has created a thermally responsive 4D-printed metamaterial that delivers unprecedented broadband, tunable microwave absorption. Published in Science Advances, the pyramidal structure, made of hierarchically porous carbon-supported high-entropy ceramic (HEO@C) and shape memory elastomer, achieves a record 14.16 GHz effective absorption bandwidth (≥90% absorption)—a 198.88% jump over its bulk counterpart. Triggered by a mild 120°C heat stimulus, it reconfigures on demand, tuning absorption across 5.24–18 GHz while maintaining ≥99% absorption (reflection loss <−20 dB).

A novel dual-scale mechanism was found that drives this performance: microscopically, lattice distortions, oxygen vacancies in HEO, and charge transfer at carbon-ceramic interfaces generate multi-level polarization losses; macroscopically, programmable cavity deformation alters the dielectric space, exciting multi-frequency resonances. This innovation eliminates fixed-geometry limitations of traditional absorbers without fragile mechanical/pneumatic actuators. It also enables adaptive electromagnetic protection for 5/6G communications, radar stealth, and microwave therapy, shielding electronics and human health from harmful radiation. Here is the full article published in Science Advances.