THE MICROSTRUCTURE AND DIELECTRIC PROPERTIES OF Sm_2O_3 DOPED Ba_(0.6)Sr_(0.4)TiO_3-MgO COMPOUND FOR PHASE SHIFTERS

摘要

The structural, surface morphological, tunable and dielectric properties of Sm_2O_3 doped Ba_(0.6)Sr_(0.4)TiO_3-MgO ceramics were investigated. Sm_2O_3 dopant effectively decreases the dielectric loss of BST-MgO ceramics. 0.2wt% Sm_2O_3 additives dramatically weaken the uniform of grains distribution and deteriorated the tunable ability. More uniform grains were observed with higher Sm_2O_3 concentration. The ε-E~2 characteristic is an indicator of the uniformity of grains in BST-MgO composite. For 1.2wt% Sm_2O_3 doped samples, the microwave loss at 2.5GHz is 0.00478 and the tunability is 6.52%, it basically meets the requirements of phase shifters.