xMgWO(4)-(1 - x)Ba(0.5)St(0.5)TiO(3) (x = 0.0, 5.0, 15.0, 25.0 and 35.0 wt%) composite ceramics were prepared via solid state reaction processing. Their structural and dielectric properties were systematically characterized. A significant increase in grain size was observed with increasing MgWO4 content, which was accompanied by obvious variations in dielectric properties of the composite ceramics. It is found that the permittivity peaks of the samples gradually shifted to low temperatures with increasing MgWO4 content. At the same time, tunabilities of the composite ceramics decreased, but their Q values increased. The sample with 35 wt% MgWO4 possesses a high tunability of 16.8%(similar to 10 kHz), a low permittivity of 65 and an appropriate Q value of 309 (similar to 4.303 GHz), which meet the requirements of high power and impedance matching, thus making it a promising candidate for applications as electrically tunable microwave devices. (C) 2011 Elsevier Ltd. All rights reserved.