Flexible and broadband metamaterial for microwave absorption achieved by laser etching of carbon fiber-loaded silicone composite

This study presents the development of a flexible, lightweight, and broadband electromagnetic absorber based on a silicone-carbon fiber composite structured via CO₂ laser etching. The composite, fabricated using silicone resin loaded with 100 µm carbon fibers (15 wt.%), offers a high flexibility and low density (1.09 g/cm³). A metamaterial architecture based on two-unit cells is etched into the composite to enhance absorption performance, addressing the limitations of conventional absorbers such as high density, rigidity, and narrow bandwidth. Parametric studies were conducted to optimize the composite conductivity (0.5–50 S/m), absorber thickness (1-2 mm), and laser etching depth. The configuration with a conductivity of 1 S/m and 2 mm thickness provides the widest absorption bandwidth, extending from 5 to 18 GHz. Measurements performed in an anechoic chamber confirm broadband absorption under normal and oblique incidence (30°). Figure of merit, calculated using thickness, lowest absorption frequency and bandwidth, outperforms existing flexible absorbers.