Computer simulation of direct-current field dependence of the dielectric constant of Al₂O₃-doped barium stronium titanate in the paraelectric state

Effects of a DC field on the real part of the relative dielectric constant of Al₂O₃-doped barium strontium titanate for application in phased array antennas have been studied. The real part of the relative dielectric constant of the specimens decreases when the applied DC field is increased. The tunability is about 24% for barium strontium titanate doped with 1 wt% Al₂O₃. Curve fitting only works well for pure barium strontium titanate. The real part of the relative dielectric constant of Al₂O₃-doped barium strontium titanate decreases rapidly before 1.0kV/cm and slowly after 1.0kV/cm when compared to the data obtained by curve fitting. This can be explained by the space charge polarization theory.