Microwave dielectric properties of Li₂WO₄ ceramic with ultra-low sintering temperature

A new ultra-low-temperature firing microwave dielectric ceramic, Li ₂WO₄ with the phenacite structure, was prepared via solid-state reaction method. The Li₂WO₄ ceramic can be well sintered at 640°-660°C, with a microwave relative permittivity ∼5.5, a Q×f value about 62 000 GHz, and a negative temperature coefficient of -146 ppm/°C at 15.7 GHz. From an X-ray diffraction analysis, the Li₂WO₄ ceramic was found to be chemically compatible with both silver and aluminum powders at 640°C. All the results indicate that the Li₂WO₄ ceramic is a promising candidate for ultra-low temperature cofired ceramic technology, especially for dielectric substrate application.