A new high-Q×f Li4NbO4F microwave dielectric ceramic for LTCC applications

A novel microwave dielectric ceramic material, Li4NbO4F, was fabricated by the solid-state reaction method. The microwave dielectric properties, sintering characteristics, and crystal structures of the Li4NbO4F ceramic samples were investigated. It was found that the Li4NbO4F ceramic samples can be successfully sintered at low temperatures (e.g., 750–875 °C). The samples exhibited a single cubic rock salt phase and possessed homogenous microstructures and outstanding microwave dielectric properties. The optimal properties of Q × f = 61111 GHz, er = 15.2, and τƒ = −51 ppm/°C were achieved in the ceramic sample sintered at 825 °C. Additionally, the ceramic samples showed superior compatibility with Ag, indicating that Li4NbO4F is a promising low-temperature co-fired ceramic (LTCC) material.