Ultrabroadband metastructure absorber with angular stability for conformal applications

The sustained growth and development of numerous microwave electronic facilities have boosted the demands for microwave absorbers with high performance in bandwidth, wide incident angle, and adaptability of the curved surface. To satisfy these requirements, a 3D-printed electromagnetic metastructure based on a new design methodology with comprehensive microwave absorption properties was proposed and manufactured in this work. The multi-resonant metastructure based on the composite of polyether-ether-ketone and flaky carbonyl iron was designed, and then the gradient impedance distribution was optimized via simulation and comparison of the broadband impedance matching and microwave attenuation properties in different polarization modes under oblique incidence, followed by structural parameters optimization to achieve the optimal absorption performance with broadband and wide incident angle. In the meantime, the conformal capacity of the metastructure under different types of curved surfaces was also investigated. Experimental results correlated well with simulations and demonstrated excellent absorption performance with effective absorption in the broad frequency range of 3.3–30 GHz, stable absorption in the wide incident angle of 0°–70° for both transverse electric and transverse magnetic polarization modes, and strong backward scattering suppression for different conformal states. This effective strategy will provide a novel and promising route toward the development of microwave absorption metastructures with comprehensive electromagnetic performance and accelerate the applications in electromagnetic protection.