Perovskite compounds, SrxNd2(1-x)/3TiO3 (SNTx) with x ranging from 0.05 to 0.2, were prepared by the conventional solid-state reaction method. X-ray diffraction patterns illustrated that high density and single phase products were obtained for all samples, indicating that a small level of Sr addition could substantially stabilise the structure and maintain a single phase for Nd2/3TiO3 ceramics. But there was also an orthorhombic space groups transition from Pnma to P4/mmm when x was above 0.18. In addition, the dielectric constant (epsilon(r)) of SNTx ceramics had improved from similar to 85.6 to similar to 112 with increasing x value due to the larger ionic polarizability of Sr2+ than that of Nd3+. Notably, the product of dielectric Q value and resonant frequency (Q x f) of similar to 295-650 at 3.07-3.32 GHz was strongly dependent on the grain size and the cation deficient in the present systems. Either increasing grain size or decreasing A-site vacancies led to an increase in the Q x f value. Besides, a temperature coefficient of resonant frequency (tau(f)) of the SNTx ceramics sintered at their optimum densification temperature gradually increases from 191.7 ppm/degrees C (x = 0.05) to 221.3 ppm/degrees C (x = 0.2), which results from the lower rattling effect and higher symmetry in BO6 octahedra of perovskite structure according to bond valence theory and tolerance factor (t). (C) 2016 Elsevier B.V. All rights reserved.