Effect of LiF and LBSCA glass on the microwave dielectric properties of 0.5BaCuSi4O10–0.5BaCuSi2O6‐based ceramics for LTCC applications

In this work, the 0.5BaCuSi4O10–0.5BaCuSi2O6‐based ceramics were synthesized using a standard solid‐phase reaction process, and the inherent relationship between crystal structure and microwave dielectric properties was thoroughly explored. The crystal structure of the 0.5BaCuSi4O10–0.5BaCuSi2O6 ceramic was determined by X‐ray diffractometer, which confirmed the existence of two phases. Microstructure observation of the ceramics was obtained by scanning electron microscope (SEM). Excellent microwave dielectric properties with a low ԑr ∼6.52, a high Q × f ∼46 010 GHz, and the temperature coefficient of resonant frequency (TCF) ∼−14 ppm°C−1 were obtained in the 0.5BaCuSi4O10–0.5BaCuSi2O6 ceramic sintered at 1060°C. By adding sintering additives LiF and Li2O–B2O3–SiO2–CaO–Al2O3 (LBSCA) glass, the sintering temperature was decreased from 1060°C to 870°C. Good microwave dielectric properties with a ԑr ∼6.59, a Q × f ∼18 820 GHz, and TCF ∼−14 ppm°C−1 were achieved in the 0.5BaCuSi4O10–0.5BaCuSi2O6 ‐2 wt.% LiF, 1 wt.% LBSCA (2F1LBSCA) ceramic sintered at 870°C. The low‐temperature firing ceramics could also be well co‐fired with Ag with good chemical compatibility. These results indicated that the 0.5BaCuSi4O10–0.5BaCuSi2O6 ceramic with 2F1LBSCA additions can be utilized in low‐temperature co‐fired ceramics technology to produce high‐frequency communication components.