The effects of sintering temperature on the microwave dielectric properties and the microstructure of CaO- Li 2O-Sm 2O 3-TiO 2 ceramics were investigated. CaO-Li 2O-Sm 2O 3-TiO 2 with the composition CaO : LiO 2 : Sm 2O 3 : TiO 2 = 16 : 9 : 12 : 63 was previously proposed as an excellent microwave dielectric material. Although the proposed composition was reported to consist of the perovskite phase with residual TiO 2 as the second phase, the X-ray reflection lines of TiO 2 were not detected in our specimens. The structure of our specimen was that of an orthorthomic perovskite throughout the entire range of sintering temperature (1250°C ∼ 1370°C). The dielectric properties were found to strongly depend on the sintering conditions. The dielectric constant and temperature coefficient for the resonant frequency were found to decrease as the sintering temperature increased, while the Q.f value exhibited a different trend: The material showed a maximum Q.f value of 5700 (GHz) for sintering at 1310°C. At 1350°C, the dielectric properties with an ε r value of 102, a Q.f value of 5150 and a T f value of 8 ppm/°C were suggested for practical applications.
|Number of pages||5|
|Journal||Proceedings of the National Science Council, Republic of China, Part A: Physical Science and Engineering|
|Publication status||Published - 2001 Sep 1|
All Science Journal Classification (ASJC) codes