Microwave dielectric ceramics in (Mg1/3Sb2/3)O2-ZrO2-TiO2 system with near zero τf and low loss in a very wide range

A series of (ZrTi)(1-x)(Mg1/3Sb2/3)(2x)O-4 (0.04 <= x <= 0.36) ceramics were successfully synthesized through the conventional solid-state processing. Appropriate content of CuO was added as sintering aids to promote the density of ceramics. The XRD analysis revealed that the main crystalline phase of ceramics sintered at optimal temperature belonged to alpha-PbO2-type structure. Raman spectroscopy and far infrared reflectivity (FIR) spectra were employed to study the phonon modes of ceramics, which explained the relationship between microwave dielectric properties and structure. It is interesting that the tau(f) are near-zero ( + 6.6 similar to - 4.6 ppm/degrees C) and meanwhile the Q x f are relatively high (29,000-41,800 GHz) for samples with x in a very wide range of 0.10-0.36. In this range, their dielectric constants (epsilon(r)) can be adjustable from 35.4 to 24.4. The results demonstrated this ceramic system is a potential candidate for microwave dielectric applications requiring an adjustable dielectric constants and near zero tau(f).