Additive Manufacturing of a 460mm-diameter Flat Off-axis Lens for Ka-band Communications

This article presents a large-aperture flat off-axis lens operating in the Ka-band around 30 GHz and fully 3D-printed by FDM (Fused Deposition Modelling) technique with a high-permittivity dielectric material. The refractive index profile, which is required to transform a spherical wave into a tilted plane wave, is implemented by structuring the material at a sub-wavelength scale. The fabricated 460mmdiameter off-axis lens is composed of around 20 000 circular pillars whose diameter varies from 0.8 mm to 2.6 mm. To the best of our knowledge, this is the first RF component made by additive manufacturing with such a large dimension associated to such a high precision and resolution. Simulation and preliminary measurement results show a good agreement, that confirms the possibility to exploit 3D-printing for large-aperture planar lenses operating in millimeter wave bands.