Design and characterization of a lightweight and flexible carbon fiber-loaded silicone foam-based broadband metamaterial absorber for microwave applications

This study reports a simple fabrication technique for creating a flexible, organic, and microwave-absorbing material using carbon fiber-loaded silicone foam. The \"particle-template\" elaboration method, using sugar crystals as sacrificial particles, is conducted. The material's density is adjusted by varying the sugar crystal concentration while ensuring effective dispersion of carbon fibers in the silicone foam matrix. The dielectric characterization of a composite with a density of 0.33 g.cm−3 and loaded with 2 wt.% of 12 mm carbon fibers results in a permittivity ranging from 7 to 1.1 and a dielectric loss ranging from 1.9 to 0.7 across the frequency range of 2–18 GHz. These properties are used in a parametric study to optimize the overall dimensions of a structured absorber to achieve wideband absorption performance. The resulting prototype, with a total thickness of 16 mm, demonstrates promising performance by exhibiting broadband absorption (4–18 GHz), as predicted by simulation.