Research and simulation of three-layered lightweight cement-based electromagnetic wave absorbing composite containing expanded polystyrene and carbon black

Based on impedance gradient principle, a three-layered lightweight and broadband electromagnetic wave (EMW) absorbing cement-based composite is designed and prepared using expanded polystyrene (EPS) and carbon black (CB) as wave-transparent and absorbent medium, respectively. The three-layer absorber indicates excellent EMW absorbing properties in 1.1–18 GHz frequency range due to the good impedance matching and attenuation capacity. The minimum value of reflection loss (RL) is –49.6 dB with a 7 cm thickness and an effective absorbent bandwidth (RL < –20 dB) of 14.32 GHz can be achieved at a thickness of 8 cm. Furthermore, the idealized EPS-cement/CB structure model is established and simulated by finite element method in X-band. The propagation process of EMW is visual and greatly affected by EPS, and the electric field distribution presents a circular loop. Here the Smith chart can be used to analyze the impedance source of each circular loop at different frequencies. What’s more, the density of three-layered composites is between 170–250 kg/m3, meeting the requirements of lightweight, and the compressive strength of single-layer composite reaches about 0.65 MPa when the density is 350 kg/m3. Thus, the three-layer lightweight EPS-cement/CB composite is a promising EMW absorber with broadband absorption performance, which could be used for protecting buildings from electromagnetic interference.