A novel mini 0.95MgTiO₃-0.05CaTiO₃ ceramic Luneburg lens fabricated by vat-photopolymerization 3D printing

With 5G and millimeter-wave technologies evolving rapidly, the high communication frequency leads to high integration and miniaturization of the Luneburg lens (LL). In this paper, a miniaturized K-band flat LL with 0.95MgTiO₃–0.05CaTiO₃ (95MCT) ceramic was designed and successfully printed by vat-photopolymerization 3D printing. Optimal 3D printing parameters and thermal treatment processes of 95MCT ceramic were investigated. The as-prepared 95MCT ceramic showed excellent properties: a density of 3.40 g/cm³, a high flexural strength of 81.78 MPa, a dielectric constant of 17.7, and a remarkably low dielectric loss value of 4.56 × 10^-4. Based on the 95MCT ceramic, a flat LL with a diameter of 40 mm and thickness of 6 mm was printed with sophisticated metastructure. While miniaturization was accomplished with a high degree of dimensional compression, the printed flat LL showed a maximum gain enhancement over 5 dBi. Thus, this study provides a novel viewpoint on the fabrication of microwave dielectric ceramic and miniaturized ceramic radio frequency (RF) devices with complex structures.