Microwave dielectric properties of two low temperature sintering ceramics in the PbO-WO₃ binary system

Abstract Two microwave dielectric ceramics in the PbO-WO₃ binary system, PbWO₄ and Pb₂WO₅, with low sintering temperatures were prepared by a conventional solid-state reaction method. The Pb₂WO₅ ceramic could be well densified at around 520°C and demonstrated high performance microwave dielectric properties with a relative permittivity ∼16.4, a Q×f value ∼14,805 GHz (at 7.6 GHz), and a negative temperature coefficient of resonant frequency ∼ -94.5 ppm/°C. The PbWO₄ ceramic could be well densified at around 620°C with a larger relative permittivity ∼21.4, a higher Q×f value ∼43,000 GHz (at 7.0 GHz), and a nearly zero temperature coefficient of resonant frequency ∼ -7.1 ppm/°C. From the X-ray diffraction pattern, backscattered electron image and energy dispersive spectrometer analysis results of the co-fired samples with 20 wt% Ag or Al additive, the PbWO₄ and Pb₂WO₅ ceramics did not react with either Ag or Al powders at their optimum sintering temperature.