Effect of TiO2 ratio on BaO-Nd2O3-TiO2 microwave ceramics

The dielectric properties of BaO-Nd2O3-TiO2 ceramics with various TiO2 contents at microwave frequencies were investigated, by varing the range of composition from 1:1:4 to 1:1:5 (BaO:Nd2O3:TiO2). Sintered ceramics were studied by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and dielectric data measured at microwave frequencies. The XRD results revealed that the matrix phase was BaNd2Ti5O14, and that BaTi4O9 and Ba2Ti9O20 secondary phases were present. The dielectric constant saturates at 80-83 with various TiO2 content. Q × f values of 5700-11,560 (at 4 GHz) can be obtained by doping with various the ratio of TiO2, sintering at 1300 °C for 2 h. The temperature coefficient of resonant frequency ranges from 62 to 151 ppm/°C.