| Title |
Dielectric Properties of Al_2O_3-Doped (Ba, Sr, Ca)TiO_3 Ceramics for Phased Array Antenna |
| Authors |
이성갑(Lee, Seong-Gap) ; 이영희(Lee, Yeong-Hui) |
| Keywords |
barium strontium calcium titanate ceramics ; dielectric constant ; dielectric loss ; tunability |
| Abstract |
(Ba_{0.6}Sr_{0.4}Ca_x)TiO_3 + yAl_2O_3 wt% (x=0.10, 0.15, 0.20, y=0~3.0) ceramics were fabricated by the mixed-oxide method, and their structural and dielectric properties were investigated with variation of composition ratio and Al_2O_3 doping content. As results of the X-ray diffraction and microstructure analysis, all BSCT specimens showed dense and homogeneous structure without presence of the second phase. The sintered density was decreased with an increase of Al_2O_3 doping content. The Curie temperature and relative dielectric constant at room temperature were decreased with increasing Al_2O_3doping content. The dielectric loss is minimum at BSCT doped with 1.5wt% Al_2O_3content. The tunability was decreased with increasing an Ca content and the BSCT(50/40/10) specimen doped with 2.0wt% Al_2O_3content showed the maximum value of 4.2%. |