Preparation and microwave dielectric properties of low-loss MgZrNb2O8 ceramics

A novel low-loss microwave dielectric material MgZrNb2O8 was reported for the first time. Single-phase MgZrNb2O8 was prepared by a conventional mixed-oxide route and sintered in the temperature range of 1280-1360 °C. The microstructure and microwave dielectric properties were investigated systematically. The X-ray diffraction results showed that all samples exhibit a single wolframite structure. When the sintering temperature was lower than 1340 °C, the Q×f value mainly depended on the relative density. However, when the sintering temperature was above 1340 °C, the Q×f value mainly relied on the grain morphology in addition to the density. The MgZrNb2O8 ceramic sintered at 1340 °C for 4 h exhibited excellent microwave dielectric of εr=26, Q×f=120,816 GHz (where f=6.85 GHz), and τf=−50.2 ppm/°C. These results demonstrate that MgZrNb2O8 could be a promising candidate material for the application of highly selective microwave ceramic resonators and filters.