Development of a Miniature and Lightweight Zn2SiO4-TiO2 Ceramic Flat Luneburg Lens Fabricated via Vat-Photopolymerization 3D Printing

With the rapid advancement of 5G communication technology, higher communication frequencies have pushed the development of the Luneburg lens (LL) towards greater integration and miniaturization. In this paper, a novel Zn 2 SiO 4 -TiO 2 (ZST) ceramic Flat Luneburg Lens (FLL) for the K-band is designed and successfully fabricated using vat-photopolymerization (VPP) 3D printing technology. By optimizing the rheological properties of the slurry alongside the photopolymerization and thermal treatment processes, the resulting ZST ceramic exhibits excellent microwave dielectric properties after sintering at 1250 °C: a dielectric constant ( εᵣ ) of 9.6933, a quality factor ( Q×f) reaching 85294 GHz, a frequency temperature coefficient ( τ f ) close to zero (-0.78 ppm/°C), and an extremely low dielectric loss (1.29×10 -4 ). Building upon this high-performance ZST ceramic, a miniaturized FLL with a diameter of 30 mm and a thickness of 4 mm was successfully fabricated via metamaterial structural design. The measured results indicate that the FLL achieved a maximum gain enhancement of 5.5 dBi. This work offers useful insights into the 3D printing manufacturing of high-performance microwave dielectric ceramics and their application in miniaturized and integrated radio frequency devices.