Dielectric Properties of $Al_2O_3-Doped\; (Ba, Sr, Ca)TiO_3$ Ceramics for Phased Array Antenna

위상배열 안테나용 $Al_2O_3가\; 첨가된\; (Ba, Sr, Ca)TiO_3$ 세라믹의 유전적 특성

  • 이성갑 (서남대 전기전자공학부) ;
  • 이영희 (광운대 반도체 및 신소재공학과)
  • Published : 2001.11.01

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 $Al_2O_3$doping content. The dielectric loss is minimum at BSCT doped with 1.5wt% $Al_2O_3$content. The tunability was decreased with increasing an Ca content and the BSCT(50/40/10) specimen doped with 2.0wt% $Al_2O_3$content showed the maximum value of 4.2%.

Keywords

barium strontium calcium titanate ceramics;dielectric constant;dielectric loss;tunability

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