Enhanced Microwave Dielectric Properties and Sintering Behaviors of Mg2 SiO4-Li2 TiO3-LiF Ceramics by Adding CaTiO3 for LTCC and GPS Antenna Applications

• Main Authors: Ai, J. (Author), Chen, Y. (Author), Du, Q. (Author), Liu, L. (Author), Pan, F. (Author), Tang, R. (Author), Wang, Z. (Author), Zhang, H. (Author)
• Format: Article
• Language: English
• Published: MDPI 2022
• Subjects: antenna; LTCC; Mg2 SiO4-Li2 TiO3-LiF-CaTiO3 ceramics; microwave dielectric property; structure
• Online Access: View Fulltext in Publisher

 Mg2 SiO4 holds promise for its application in the microwave communication field due to its low dielectric constant and high Q×f value. However, its high negative τf and high sintering temperature limit its application in low-temperature co-fired ceramic (LTCC) devices. In this work, Li2 TiO3 and CaTiO3 were introduced to improve the τf, and LiF was chosen to decrease the sintering temperature. According to XRD patterns and SEM micrographs, the ceramic systems displayed a complex-phase structure, and the microstructure was densified when CaTiO3 was added. All of the relative densities, dielectric constants, and Q×f values first increased and then decreased as the sintering temperature increased. The MLLC11.5 ceramics sintered at 800◦ C could be obtained with the highest Q×f value of 54,581 GHz (at 8.06 GHz), εr of 14.13, and τf of + 5.81 ppm/◦ C. Furthermore, it was proven that the MLLC11.5 powders could be co-fired without any reaction with Ag powders at 800◦ C, indicating its potential for LTCC application. The MLLC11.5 composition was used to prepare a GPS antenna and showed good prospects for its application in electronic communications. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.