By using a sol-gel process under solvothermal conditions (SGS), the (1 - x)SiO2-xTiO(2) (0.1 <= x <= 0.3) composite powders with a core-shell structure were prepared and its microwave dielectric properties were investigated for the first time. The 0.85SiO(2)-0.15TiO(2) ceramics sintered at 1200 degrees C possess excellent microwave dielectric properties of epsilon(r) similar to 5.4, Q.f similar to 40,500 GHz and tau(f) near to 0 ppm/degrees C. The optimum sintering temperature was reduced 475 degrees C compared to that by a conventional solid-state method. (C) 2014 Elsevier Ltd. All rights reserved.