Conventional microwave-absorbing coatings struggle to achieve broadband absorption over a wide range of angles while also serving structural purposes. Multistage metastructures offer more design flexibility, but it is difficult to optimize their many interacting geometric parameters.

In a study published in Chemical Engineering Journal, a team led by Prof. WANG Zhenyang from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences developed an electromagnetic wave-absorbing metastructure that can absorb microwaves over a broad frequency range while also supporting loads and removing ice through electrical heating.

The structure is made from polyamide 6/carbon-fiber composite (PACF), neat polyamide 6 (N-PA), and a laser-treated PACF backing layer. The three stages work at different but overlapping frequency ranges, together covering 2–40 GHz. The layered design helps microwaves enter the structure and dissipate their energy.

Through numerical simulations and machine learning, researchers fine-tuned the shape of this three-stage truncated-cone structure. They then used a machine-learning model to select the final design and identify how different parts of the structure affect microwave absorption.

"Even with a thickness of just 14.7 mm, the structure maintains strong microwave absorption across a broad frequency range and at large incident angles. And it still performs well at an incidence angle as high as 75°," said Dr. XI Min, one of the authors of this study.

Besides, the structure reduced radar scattering and had sufficient mechanical strength to carry loads. The laser-treated backing layer enabled electrothermal deicing. At 25 V, it reached about 48 °C and melted a 3-mm-thick ice layer within 60 seconds at around 0 °C.

The proposed design offers a practical option for the applications requiring both electromagnetic protection and structural strength.