Microwave dielectric properties of 0.85CaWO4–0.15SmNbO4 ceramics with sintering additives

Low-temperature sintering and microwave dielectric properties of 0.85CaWO4–0.15SmNbO4 (CWSN) ceramics were investigated as a function of Li2MoO4 and/or Li2WO4 content. With an addition of Li2MoO4 and/or Li2WO4, the sintering temperature could be reduced from 1150 °C for pure CWSN ceramics to 800 °C. The dielectric constant (K) was not changed remarkably with Li2MoO4 and/or Li2WO4 content. Quality factor (Qf) of the specimens was decreased with Li2WO4 content, while that of the specimens was increased with Li2MoO4 content. Qf values of the specimens with 1.0 wt.% Li2WO4 showed larger value than that of the specimens with 2.5 wt.% Li2MoO4. The temperature coefficient of resonant frequency (TCF) was shifted to the positive value with increasing Li2WO4 and/or Li2MoO4 content. Typically, K of 12.03, Qf of 13,300 GHz and TCF of −28.6 ppm/°C were obtained for the specimens with 1.0 wt.% Li2WO4 sintered at 800 °C for 1 h.