Microwave dielectric properties of Mg-3(VO4)(2)-xBa(3)(VO4)(2) ceramics for LTCC with near zero temperature coefficient of resonant frequency

The Mg-3(VO4)(2-x)Ba-3(VO4)(2) ceramics have been investigated to obtain a low-temperature co-fired ceramic (LTCC). The highest quality factor (Q(f)) of approximately 114,000 GHz was obtained when the ceramic with x = 0.2 was sintered at 950 degrees C for 5 h in air. The temperature coefficient of resonant frequency (tau(f)) of the ceramics sintered at 1025 degrees C varied from -90 to 60 ppm/degrees C as the amount of xBa(3) (VO4)(2) increased, and was a near zero value in the sample obtained at x = 0.5 where the dielectric constant (epsilon(r)) and the Q(f) values were approximately 12 and 55,000 GHz, respectively. In order to reduce the sintering temperatures of Mg-3 (VO4)(2-x)Ba-3 (VO4)(2) ceramics, the effects of Li2CO3 addition as a sintering aid on the microwave dielectric properties of Mg-3(VO4)(2)-0.5Ba(3)(VO4)(2) ceramics were also characterized in this study. The Li2CO3 addition was effective in reducing the sintering temperature without detrimental effects on the Qf values of the ceramics. One result: the microwave dielectric properties of Mg-3(VO4)(2)-0.5Ba(3)(VO4)(2) with 0.0625 wt%-doped Li2CO3 ceramic, which was sintered at 950 degrees C for 5 h in air, has a epsilon(r) value of 13, a Q(f) value of 74,000 GHz, and a tau(f) value of -6 ppm/degrees C. (c) 2006 Elsevier Ltd. All rights reserved.