Microwave dielectric properties of (1−x)ZnTa2O6−xMgNb2O6 ceramics

Single phase MgNb2O6 and ZnTa2O6 powders were synthesized by solid-state method, and the high quality factor composite ceramics of (1−x)ZnTa2O6−xMgNb2O6 (x=0, 0.05, 0.10, 0.15, 0.20, 0.25 and 1.0) were prepared using the as-synthesized powders. The microwave dielectric properties, microstructure, phase transition and sintering behavior of the composite ceramics were investigated. The X-ray diffraction analysis revealed that solid solution between ZnTa2O6 and MgNb2O6 phases appeared in the composite ceramic. SEM results show that the grain sizes of the composite ceramics increased with increasing x values. The temperature coefficient of resonant frequency of (1−x)ZnTa2O6−xMgNb2O6 composite ceramics reaches near-zero of 1.02 ppm/°C with εr=35.58 and a high quality factor of 65500 GHz when x=0.20 and sintered at 1350 °C for 2 h.