A novel low-fired, temperature-stable, and low-cost (1−x)BaCu(B2O5)−xTiO2 microwave dielectric ceramic

BaCu(B2O5) is a typical microwave dielectric ceramic (MDC) with a low sintering temperature, but it exhibits a large negative temperature coefficient of resonant-frequency (τf) which makes it difficult to use in wireless communications. We employ TiO2 to improve its temperature-stability of resonant-frequency, and reveal the effects of TiO2 on the densification and the microwave dielectric properties of BaCu(B2O5). Here we show that BaCu(B2O5) can be well-sintered at 825 °C with proper TiO2 additions; we find that the TiO2 grains homogeneously distribute in the boundaries of BaCu(B2O5) grains, resulting in the τf compensation of BaCu(B2O5). Enhanced temperature-stability of resonant-frequency can be achieved by increasing the content of TiO2 properly. A novel temperature-stable (1-x)BaCu(B2O5)–xTiO2 (x = 0.20) MDC (τf =−0.8 ± 3.0 ppm/°C, εr = 8.8 ± 0.36, Q×f = 28,612 ± 1170 GHz) is obtained using some low-cost raw materials. Our results provide the underlying insights needed to guide the design of temperature-stable MDCs for wireless communication applications.