Two low-εr phenakite-structure LiAGeO4 (A = Al, Ga) microwave dielectric ceramics with different structure ordering. Issue 8 (15th April 2021) - Yang, Zijian
Abstract: Two types of hexagonal phenakite-structure LiAGeO4 (A = Al, Ga; named LAG and LGG, respectively) ceramics were prepared by the conventional solid-phase method. Associated with the phase composition, crystal structure and sintering behavior, the microwave dielectric properties of LAG and LGG ceramics were researched. When sintered at 1100 °C and 1075 °C, LAG and LGG ceramics with a space group of R3 and R 3 ‾, exhibited favorable microwave dielectric properties: low ε r ~ 5.45 and 6.07, high Q × f ~ 70, 832 GHz and 30, 065 GHz, and negative τ f ~ −34.4 ppm/°C and −60.3 ppm/°C, respectively. Their intrinsic dielectric properties were analyzed by infrared reflectivity spectra. Additionally, TiO2 was added to tune the τ f of LAG and LGG ceramics, and near-zero τ f values of −3.14 ppm/°C and +2.17 ppm/°C were obtained in 0.84 LAG‐0.16 TiO2 and 0.78 LGG‐0.22 TiO2 ceramics.