A kirigami-based strain-insensitive stretchable metastructure with ultra-broadband microwave-absorbing

Stretchable microwave-absorbing metastructures (SMAMSs) that provide the ability to hide complex objects from radars have long been of interest. However, recent studies of SMAMSs have demonstrated the operating frequency can undergo alteration even at relatively modest tensile strain. Herein, a SMAMS with strain-insensitive performance was proposed. This composite structure is composed of a kirigami-based stretchable TPU substrate and electromagnetic dissipative (EMD) units. The proposed SMAMS demonstrates an ultra-broadband microwave-absorbing performance (| S 11 | < −10 dB) from 1.3 to 40.0 GHz under normal incidence, with a thickness of 30 mm. The microwave-absorbing performance exhibits strain-insensitive properties, with only a 0.3 GHz operating band shift to higher frequencies under 40% tensile strain. As a proof of concept, the SMAMS was applied to both flat and curved surfaces. The findings of both the simulation and experimental results indicated that the SMAMS successfully maintained its initial 10 dB reduction in radar cross-section (RCS) bandwidth. Highly stretchable of kirigami-based substrate combined with the strain-insensitive EMD units provides a novel strategy paradigm to design stretchable microwave-absorbing devices.