초록 close

- In this study, both structural and microwave dielectric properties of the Mg5B4O15 (B=Ta, Nb) cation-deficient perovskite ceramics with sintering temperature were investigated. All sample of the Mg5B4O15 (B=Ta, Nb) ceramics were prepared by the conventional mixed oxide method and sintered at 1400℃~1500℃. The bulk density and quality factor of the Mg5B4O15 (B=Ta, Nb) ceramics were increased with increasing sinterning temperature in the range of 1400℃~1450℃, but these were decreased the sintering temperature of above 1450℃. The dielectric constant of the Mg5Ta4O15 ceramics was increased continuously with increasing sintering temperature. And the dielectric constant of the Mg5Nb4O15 ceramics was increased in as the sintering temperature increasesfrom 1400℃~1450℃ but was decreased at the temperatures above 1475℃. In the case of the Mg5Ta4O15 and Mg5Nb4O15 ceramics sintered at 1450℃ for 5h, the dielectric constant, quality factor, and temperature coefficient of the resonant frequency (TCRF) were 8.2, 259,473 GHz, -10.91 ppm/℃ and 14, 37,350 GHz, -52.3 ppm/℃, respectively.