New High-Permittivity AgNb1-xTaxO3 Microwave Ceramics: Part II, Dielectric Characteristics

Ceramic samples with the AgNb1−xTaxO3 (0.46 410, whereas the Q×f value, measured at 2 GHz, reaches values of 640–900 GHz. Dependence of the resonant frequency on temperature was not linear but did display a minimum at a particular temperature, which was dependent on the composition of the ceramic. Samples that were measured at radio frequencies displayed low dissipation factors (tgδ= 7 ×10−4−18 × 10−4), a low aging rate (0.2% per time decade), and good dielectric strength (8 V/μm at a thickness of 0.6 mm). Microstructural investigations revealed the presence of precipitates and transformation twins that should be eliminated during additional processing optimization.