Microwave dielectric properties of (Pb1−3x/2Lax)(Mg1/2W1/2)O3

La modified Pb(Mg1/2W1/2)O3 were prepared by solid-state reaction process, and the sintering behavior, microstructure and microwave dielectric properties were investigated by X-ray powder diffraction (XRD), Raman scattering and HP network analyzer in this paper. A series of single phase perovskite type solid solutions with A-site vacancies (Pb1−3x/2Lax(Mg1/2W1/2)O3 (0 ≤ x ≤ 2/3)) were formed. The solid solution took cubic perovskite type structure (Fm3m) with random distribution of A-site vacancies when 0 < x < 0.5, and tetragonal or orthorhombic structure with the ordering of A-site vacancies when 0.5 ≤ x ≤ 2/3. The dielectric constant and temperature coefficient of resonant frequency decrease with increasing La content. Relatively good combination microwave dielectric properties were obtained for x = 0.56: ɛr = 28.7; Q × f = 18098; and τf = −5.8 ppm/°C.