The observation and prediction of constant quality factors of LnAlO3 doped Ba6-3xLn8+2xTi18O54 (Ln = Nd, Sm, La) ceramics

Usually, the quality factor of a binary-phase ceramic will increase if the volume molar ratio of the high quality factor component increases, and vice versa. However, the quality factor of the Ba6-3xLn8+2xTi18O54 - LnAlO3 (Ln = Nd, Sm, La) ceramics keeps a constant (~ 2200 ± 200 at 4 GHz) as the volume molar ratio of LnAlO3 (~ 9000 at 7 GHz) increases. While previous studies reported the importance of microstructure variation, here by fitting the dielectric constant, via definition we derived a quality factor calculation formula that can precisely determine the quality factor as the volume molar ratio changes, which is of great significance for guiding the ceramic manufacturing.