Electromagnetic characteristics and 3D-printing realization of a lightweight hierarchical wave-absorbing metastructure for low-frequency broadband absorption

Electromagnetic absorbing metastructure with low frequency and broadband absorbing capacity is desir-able for scientific community and real-life application. Here, we designed a lightweight hierarchical wave -absorbing metastructure by replacing the facets of the stepped structure with smaller-scale square grid. The electromagnetic characteristics of high-efficiency absorption in low and high frequency ranges were also studied. The specific dielectric constant and dielectric loss were found to be the key factors of low -fre-quency absorption, which was realized by regulating the proportion of Ag-Cu alloy-based composite ma-terial based on fused deposition modeling 3D printing technology. The hierarchical gradient design for the wave-absorbing metastructure is helpful to not only being lightweight but also enhancing the electro-magnetic wave absorbing capacity. The existing heterogeneous interfaces of flaky alloy particles and spheric polymer particles also enhance the dielectric properties of composite material. The fabricated wave -ab-sorbing metastructure sample with the bulk density of 0.5 g/cm3 shows high-efficiency absorption in 2.5-40 GHz, and the absorbing performance keeps stable even though the incident angle varied in the range of 50 degrees. This paper provides a convenient realization method of absorbing metastructure with low frequency broadband absorption performance, which has outstanding practical application value.(c) 2023 Published by Elsevier B.V.