The La1-xBix(Mg0.5Sn0.5)O-3 ceramics were prepared by the conventional solid-state method with various sintering temperatures. The X-ray diffraction patterns of the La0.97Bi0.03(Mg0.5Sn0.5)O-3 ceramics revealed no significantvariation of phase with sintering temperatures. An apparent density of 6.50 g cm(-3), a dielectric constant (epsilon(r)) of 20.2, a quality factor (Q x f) of 58,100 GHz and a temperature coefficient of resonant frequency (tau(f)) of -84.2 ppm degrees C-1 were obtained for La0.97Bi0.03(Mg0.5Sn0.5)O-3 ceramics that were sintered at 1550 degrees C for 4 h. (C) 2011 Elsevier B.V. All rights reserved.