Ceramics in (1-x)SrLaAlO4-xSr(2)TiO(4) system were synthesized in the entire range of 0 <= x <= 1 by a standard solidstate reaction method. X-ray diffraction patterns revealed a single solid solution phase Sr1+xLa1-xAl1-xTixO4 with K2NiF4-type structure. The cell refinement showed the linear variation of lattice parameters a, c, and cell volume. With increasing x, er increased from 17.6 to 31.0, whereas tau(f) was tuned from -32 to 122 ppm/degrees C. The Qf value first increased and then decreased with increasing x due to the result of competition balance between the effect of layer mismatch and interlayer polarization. The degradation of Qf value in the vicinity of x = 0.2 could be attributed to the compositional fluctuation and inhomogeneity originated from the positive mixing enthalpy Delta H-mix, which could be confirmed by TEM observation. The best combination of microwave dielectric characteristics was achieved at x = 0.4: epsilon(r) = 18.5, Qf = 95 000 GHz, tf = -8.9 ppm/degrees C.