Highly stretchable radar absorber based on kirigami metastructures with tunable electromagnetic properties

• Published in: Acta mechanica Sinica Vol. 41; no. 9
• Main Authors: Ding, Weimin, Zhang, Zhong, Duan, Shengyu, Zhao, Zeang, Lei, Hongshuai
• Format: Journal Article
• Language: English
• Published: Beijing The Chinese Society of Theoretical and Applied Mechanics; Institute of Mechanics, Chinese Academy of Sciences 01.09.2025; Springer Nature B.V
• Edition: English ed.
• Subjects: Absorption spectra; Aircraft configurations; Algorithms; Classical and Continuum Physics; Computational Intelligence; Curved panels; Elastic analysis; Electromagnetic absorption; Electromagnetic properties; Engineering; Engineering Fluid Dynamics; Flat surfaces; Microwave absorption; Morphing aircraft; Numerical analysis; Optimization; Poisson's ratio; Polyurethane resins; Radar absorbers; Research Paper; Stealth technology; Stretching; Surface chemistry; Surface structure; Theoretical and Applied Mechanics; Urethane thermoplastic elastomers; Flexible kirigami structure; Electromagnetic tunability; Integrated optimal design; Microwave absorbing metastructure; Complex surface applicability
• ISSN: 0567-7718; 1614-3116
• DOI: 10.1007/s10409-024-24363-x

The demand for lightweight and multifunctional surface structure in high-end equipment is steadily growing. The harmonization between flexibility and electromagnetic tunability has become a significant subject for stealth morphing aircraft. This paper presents a microwave absorbing structure based on the kirigami configuration, aiming at improving the conformality with the negative Poisson’s ratio characteristic and expanding the radar stealth range with tunability. A precise electromagnetic reflectivity model of the impedance surface was established by the inversion method, and an integrated optimization algorithm was employed to optimize the structural parameters based on numerical analysis. Specimens composed of thermoplastic polyurethane elastic colloids and resistive materials were prepared to assess the in-plane mechanical tensile and electromagnetic absorption performances through experimental methods. The results indicate that the original absorption band spans 6.2–11.1 GHz, shifts to 8–18 GHz with stretching at a panel rotation angle of 16°, and remains nearly constant for further stretching. The specimens adhere to complex curved surfaces well in experiments and maintain the electromagnetic absorption performance compared with flat surfaces. This research offers a valuable reference for designing electromagnetic stealth structures that are highly stretchable and adjustable.