LAUSR

The microwave dielectric properties and the microstructures of LiMnPO4-TiO2 composite ceramics prepared by solid-state reaction method have been investigated. The results show that the pure LiMnPO4 (LMP) ceramic can be sintered at 750 °C for 4 h and has a relative permittivity (εr) of 6.7 and high quality factor (Q × f) of 41,696 GHz (at 11.2 GHz) with a temperature coefficient of resonant frequency (τf) of −55 ppm/°C. The relatively large negative τf value is lowered by preparing LMP-TiO2 composite ceramics. Adding TiO2 lowers τf from −55 to +26.8 ppm/°C, and does not induce much degradation of dielectric properties. Typically, the 19 wt% TiO2-added ceramic sintered at 875 °C for 4 h exhibits excellent properties of εr = 12.3, Q × f = 38,671 GHz, τf = 6.7 ppm/°C. Moreover, this material has a chemical compatibility with silver, making it a very promising candidate material for LTCC applications.