A novel low-firing microwave dielectric ceramic NaMg4V3O12 and its chemical compatibility with silver electrode

Abstract A tetragonal vanadate ceramic NaMg 4 V 3 O 12 was fabricated and its microwave dielectric properties were investigated. NaMg 4 V 3 O 12 ceramics could be well densified at 690 °C and exhibited favorable microwave dielectric properties with a low relative permittivity ( e r ) ~12.5, a high quality factor ( Q u ×f ) value ~35,900 GHz ( f =10.5 GHz) and a negative temperature coefficient of resonant frequency ( τ f )~−58.1 ppm/°C. NaMg 4 V 3 O 12 ceramic was found to be chemically compatible with Ag when sintered at 690 °C for 4 h. The large negative τ f value of NaMg 4 V 3 O 12 could be tuned by adding CaTiO 3 , and 0.92NaMg 4 V 3 O 12 –0.08CaTiO 3 ceramic sintered at 730 °C for 4 h exhibited a near zero τ f ~−3.8 ppm/°C with e r ~24.3, Q u ×f ~ 29,200 GHz. The results suggest it a promising ceramic for low temperature co-fired ceramic (LTCC) applications as substrate in microwave integrated circuits.