High-performance MgTiO3-CaTiO3 microwave ceramics fabricated by digital light processing and rapid microwave hybrid sintering for high-frequency communication applications

The rapid densification of ceramics printed by digital light processing (DLP) has been a technical and scientific challenge in the field of additive manufacturing. This work explores the rapid microwave hybrid sintering (MS) process for DLP-printed 0.95MgTiO 3 -0.05CaTiO 3 (MT-CT) microwave ceramics, aiming at reducing the densification time. The sintering trajectories of DLP-printed MT-CT ceramics at 1300°С show that highly dense ceramics without significant grain growth can be achieved by only 75 min and a fast heating rate (30°С/min). The MS process can enable DLP-printed MT-CT ceramics to reach the initial, intermediate, and final stages of sintering at a temperature 100 °C lower than that required for the CS process by integrating uniform volumetric heating with thermal radiation. DLP-printed MT-CT ceramics sintered by MS exhibit excellent dielectric properties: ε r  = 20.4, Q  ×  f  = 75,300 GHz, τ f  = −2.5 ppm/°C, representing a 13.4 % enhancement in Q  ×  f values compared to ceramics by CS for 240 min. DLP-printed MT-CT dielectric resonator antenna sintered by MS at 1300°С for 75 min exhibits a radiation efficiency exceeding 90 % at 5.9 GHz ( S 11  = −42.43 dB), showing their promising potential for high-frequency communication applications.