Sintering behaviors and microwave dielectric properties of Ba₃P₄O₁₃ ceramics

In this study, a Ba₃P₄O₁₃ ceramic was synthesized adopting a conventional solid-state ceramic method. Optimal microwave dielectric properties were obtained in ceramic samples sintered at 840 °C for 4 h with a ε_r (permittivity) = 7.9, a Q × f (Q = 1/dielectric loss, f = resonant frequency) = 14,200 GHz (at 11.18 GHz), and a τ_f (TCF, temperature coefficient of resonant frequency) = + 48 ppm/°C. τ_f value shifted from + 45 ppm/°C to ‒ 31.5 ppm/°C with sintering temperature rising from 860 °C to 900 °C, and this decrease in τ_f value was mainly caused by the decomposition of Ba₃P₄O₁₃ into BaP₂O₆ and Ba₂P₂O₇. Furthermore, a ceramic sample sintered at 890 °C achieved a near zero τ_f (− 1.3 ppm/°C), together with a ε_r = 7.7 and a Q × f = 13,000 GHz (at 11.44 GHz). Ba₃P₄O₁₃ ceramic has demonstrated potential as a material suitable for low-temperature co-fired ceramic technology (LTCC).