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

Abstract In this work, the 0.5BaCuSi 4 O 10 –0.5BaCuSi 2 O 6 ‐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 0.5BaCuSi 4 O 10 –0.5BaCuSi 2 O 6 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 ԑ r ∼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 0.5BaCuSi 4 O 10 –0.5BaCuSi 2 O 6 ceramic sintered at 1060°C. By adding sintering additives LiF and Li 2 O–B 2 O 3 –SiO 2 –CaO–Al 2 O 3 (LBSCA) glass, the sintering temperature was decreased from 1060°C to 870°C. Good microwave dielectric properties with a ԑ r ∼6.59, a Q × f ∼18 820 GHz, and TCF ∼−14 ppm°C −1 were achieved in the 0.5BaCuSi 4 O 10 –0.5BaCuSi 2 O 6 ‐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 0.5BaCuSi 4 O 10 –0.5BaCuSi 2 O 6 ceramic with 2F1LBSCA additions can be utilized in low‐temperature co‐fired ceramics technology to produce high‐frequency communication components.