Microwave Dielectric Properties Of Sr-Substituted Ba(Mg0.5w0.5)O-3 Ceramics

The phase evolution, microstructure, and microwave dielectric properties of Sr-substituted Ba(Mg0.5W0.5)O-3 ceramics, i.e., (Ba1-xSrx)(Mg0.5W0.5)O-3 (0 <= x <= 0.30), sintered at 1700 degrees C for 1 h were investigated. All compositions showed a 1 : 1 ordered perovskite structure. In all the compositions, BaWO4 was detected as the secondary phase. With increasing x in (Ba1-xSrx) (Mg0.5W0.5)O-3, the lattice parameter increased linearly, indicating that a substitutional solid solution occurred. All compositions exhibited a dense microstructure. The value of epsilon(r) increased slightly with increasing x. The value of Q x f(0) increased with the increase in x up to x = 0.10 and reached a saturated value of about 100,000 GHz. The composition for x = 0.20, i.e., (Ba0.80Sr0.20)(Mg0.5W0.5)O-3, sintered at 1700 degrees C for 1 h exhibited superior microwave dielectric properties of epsilon(r) = 19.6, Q x f(0) = 99,358 GHz, and tau(f) = 0.0 ppm/degrees C, respectively.