Additive manufacturing of graded-impedance metamaterial absorbers – FAMTASTIC

The FAMTASTIC (Additive manufacturing of impedance-gradient metamaterial absorbers) project is aimed at further maturing a technology for the fabrication of broadband and thin absorbing materials obtained by additive manufacturing from composite materials specifically developed for these applications.
It is the fusion of skills developed in parallel within the ASTRID 3D-MAGIC project (TRT, ICMCB, CANOE) and an academic thesis (IRDL, Lab-STICC). During the 3D-MAGIC project, building blocks were put in place in the development of printable composites (with dielectric and magnetic losses) by powder metallurgy, and in the design of compact, broadband printable periodic structures. Experimental validations have demonstrated the ability to develop an all-printed absorber covering a bandwidth of 5-20 GHz for a thickness of 9.3 mm. However, difficulties were encountered in elaborating magnetic filaments with a high magnetic particle loading rate that would enable the absorber to be more efficient at low frequencies. In parallel, IRDL and Lab-STICC worked jointly on the development of printable magnetic composites from anisotropic iron particles (flakes) during Arnaud Le Saos-Kauten's PhD thesis. It was demonstrated that anisotropic iron particles could reduce the magnetic loading ratio by 30% to 10% compared with isotropic iron fillers, to achieve similar electromagnetic (EM) properties. In addition, Arnaud Le Saos-Kauten's work has shown that 3D printing of these composites can self-induce a preferred orientation of anisotropic particles in printed parts, and thus an anisotropy of EM properties that could improve angular robustness.
The FAMTASTIC project aims to pool these skills developed in parallel to achieve three main objectives: 1) the development of innovative printable materials with anisotropic magnetic particles, 2) the development of original 3D printing processes for impedance gradients, and 3) the development of rapid design tools for broadband absorbers with anisotropic materials. Demonstrators will aim to exploit these tools and technologies to design an angularly robust broadband absorber (2-20 GHz) and a dedicated absorber for oblique incidences (60-70°).
The markets targeted by these innovations include the control of coupling and EM interference in connected vehicles, the design of compact absorbers for measurement chambers, the improvement of military radar system performance (decoupling of antenna panels, reduction of back radiation, integration on structure) and radar stealth (stealth of SCAF carriers).