Infill Dependent 3D-Printed Material Based on NinjaFlex Filament for Antenna Applications

This paper presents one of the first examples of the exploitation of 3D-printing in the fabrication of microwave components and antennas. Additive manufacturing represents an enabling technology for a wide range of electronic devices, thanks to its inherent features of fast prototyping, the reasonable accuracy, fully 3D topologies, and the low fabrication cost. A novel 3D printable flexible filament, based on NinjaFlex, has been adopted for manufacturing the substrate of a 3D printed patch antenna. NinjaFlex is a recently introduced material with extraordinary features in terms of mechanical strain, flexibility, and printability. Initially, the electrical properties of this material are investigated at 2.4 GHz using the ring resonator technique. The capability of selectively changing the dielectric constant by modifying the printed material density by fine tuning printing infill percentage is verified experimentally. Subsequently, a square patch antenna is prototyped through 3D printing and measured to validate the manufacturing technology. Finally, exploiting mechanical flexibility properties of NinjaFlex, the antenna is tested under different bending conditions.