Enhanced Microwave Dielectric Properties and Sintering Behaviors of Mg2SiO4-Li2TiO3-LiF Ceramics by Adding CaTiO3 for LTCC and GPS Antenna Applications

Mg2SiO4holds promise for its application in the microwave communication field due to its low dielectric constant and highQ×fvalue. However, its high negativeτfand high sintering temperature limit its application in low-temperature co-fired ceramic (LTCC) devices. In this work, Li2TiO3and CaTiO3were introduced to improve theτf, 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 CaTiO3was added. All of the relative densities, dielectric constants, andQ×fvalues first increased and then decreased as the sintering temperature increased. The MLLC11.5 ceramics sintered at 800 °C could be obtained with the highestQ×fvalue of 54,581 GHz (at 8.06 GHz),εrof 14.13, andτfof + 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.Keywords:Mg2SiO4-Li2TiO3-LiF-CaTiO3ceramics;structure;microwave dielectric property;LTCC;antenna