A novel spinel-type Mg3Ga2SnO8 microwave dielectric ceramic with low εr and low loss

This research used the co-substitution strategy to prepare novel spinel-type Mg 3 Ga 2 SnO 8 ceramics sintered at 1430–1510 °C. Rietveld refinement and SEM showed that the Mg 3 Ga 2 SnO 8 ceramic had a cubic spinel structure with a space group of F d 3 ¯ m ( 227 ) $Fd\overline{3}m\left(227\right)$ , where Mg1 and Mg2/Ga1/Sn1 occupy the tetrahedron and octahedron, respectively. The relative density exhibited a considerable influence on the ε r of Mg 3 Ga 2 SnO 8 ceramics. In addition, the Q × f of the ceramics was closely related to the packing fraction and FWHM. Infrared reflection spectra were used to investigate the intrinsic dielectric characteristics of the ceramics. The P−V−L theory indicated that Sn−O and Ga−O bonds contribute substantially to the ε r and Q × f , respectively. The Mg 3 Ga 2 SnO 8 ceramics had the optimum microwave dielectric properties of ε r = 9.3, Q × f = 189,052 GHz, and τ f = −34.25 ppm/°C when sintered at 1470 °C. Therefore, Mg 3 Ga 2 SnO 8 ceramics exhibit a wide range of possible applications in the field of microwave media.