Structural design and electromagnetic wave absorbing performance optimization of lightweight foam cement-based metamaterials

A novel 3D porous periodic array structural foam cement-based absorbing metamaterials (FCAM) was proposed and fabricated to defend the electromagnetic radiation issues around the building space. The electromagnetic wave (EMW) absorbing performance and mechanisms of FCAM with three different array structural units were comprehensively investigated. Thereinto, the frustum pyramid array structure was selected as an optimal structural model attributing to an ultra-broadband ( RL <-20 dB) of 13.85 GHz within the frequency of 2 -18 GHz, and high-capacity absorbing peak of-56.59 dB at 8.72 GHz. Furthermore, better impedance matching characteristics, multiple loss effects, and insensitivity of the FCAM were achieved even subjected to wide-angle oblique incidence or a variable polarization model due to the synergistic effect of the gradient structure, array structural units, and the porous matrix. Thus, this work provided an efficient method to develop high-performance cement-based EMW absorption materials and an application of wide-spectrum electromagnetic building protection technology.