Comparison of dielectric properties between Ag(Ta,Nb)O3 bulk ceramics and thick films on alumina substrate

Comparative analyses for the Ag(Ta,Nb)O-3 bulk ceramics and thick films were performed. Screen printing method was employed to prepare the Ag(Ta,Nb)O-3 thick films. For the microwave applications, crystalline and electrical properties were investigated by X-ray diffraction analysis and current-voltage characteristics, respectively. Scanning electron microscopy was also performed to evaluate the surface morphology. Dielectric permittivity of Ag(Ta,Nb)O-3 thick films was lower than that of bulk ceramics, while the loss tangent of thick films was higher compared with that of bulk ceramic. Frequency-dependent dielectric permittivity showed that Ag(Ta,Nb)O-3 thick film interdigital capacitors have very weak frequency dispersion with low a loss tangent. From the current-voltage characteristics, it was found that the Ag(Ta0.5Nb0.5)O-3 bulk ceramics and thick films had NTCR properties.