Broadband flexible metamaterial absorber on fabric using 3D-printed conductive filament patterns

The development of flexible electromagnetic absorbers is essential for next-generation electromagnetic interference (EMI) shielding and stealth applications. However, most conventional metamaterial absorbers employ rigid dielectric substrates, which limit conformability on curved surfaces and require metallic backings that increase fabrication complexity and cost. In this study, we demonstrate a metamaterial absorber by directly 3D printing conductive filament patterns onto a conductive textile substrate, eliminating the need for a dielectric spacer and metal backing. A carbon-black-loaded PLA composite was employed as the lossy material, providing sufficient dielectric loss while remaining compatible with commercial printing processes. The absorption characteristics were systematically analyzed through simulations and subsequently verified experimentally. Among the tested geometries, the split-ring resonators (SRRs) structure (outer diameter: 10.21 mm, thickness: 4 mm, spacing: 1 mm) exhibited the highest absorption performance with efficient material utilization. Furthermore, broadband simulations up to 100 GHz confirmed strong attenuation over a wide frequency range. Comparative field analyses suggest that the enhanced absorption of the SRRs geometry is associated with electric-resonance-enhanced dielectric loss, and the absorption performance is preserved under bending. This simple and scalable fabrication method offers a practical route to conformable, textile-based metamaterial absorbers for broadband EMI shielding and stealth applications.