Temperature stable K0.5(Nd1-xBix)0.5MoO4 microwave dielectrics ceramics with ultra-low sintering temperature

K-0.5(Nd1-xBix)(0.5)MoO4 (0.2x0.7) ceramics were prepared via the solid-state reaction method. All ceramics densified below 720 degrees C with a uniform microstructure. As x increased from 0.2 to 0.7, relative permittivity ((r)) increased from 13.6 to 26.2 commensurate with an increase in temperature coefficient of resonant frequency (TCF) from - 31ppm/degrees C to + 60ppm/degrees C and a decrease in Qf value (Q=quality factor; f=resonant frequency) from 23400 to 8620GHz. Optimum TCF was obtained for x=0.3 (-15ppm/degrees C) and 0.4 (+4ppm/degrees C) sintered at 660 and 620 degrees C with (r) similar to 15.4, Q(f) similar to 19650GHz, and (r) similar to 17.3, Q(f) similar to 13050GHz, respectively. Ceramics in this novel solid solution are a candidate for ultra low temperature co-fired ceramic (ULTCC) technology.