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 Ba_(6-3x)Ln_(8+2x)Ti_(18)O_(54) (Ln = Nd, Sm, La) ceramics (~ 2500 at 4 GHz) keeps a constant as the volume molar ratio of LnAlO_3 (~ 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 variation versus the volume molar ratio, which is of great significance for guiding the ceramic manufacturing
