Microwave dielectric ceramics in the Sr1-xCaxLa4Ti5O17 (0 <= x <= 1) composition series were prepared through a solid state mixed oxide route. All the compositions formed single phase ceramics within the detection limit of in-house X-ray diffraction when sintered in the temperature range 1450-1580 degrees C. Theoretical density and molar volume decreased due to the substitution of Ca2+ for Sr2+ which was associated with a decrease in the dielectric constant (epsilon(r)) and temperature coefficient of resonant frequency (tau(f)) but an increase in quality factor, Qf(o) Optimum properties were achieved for Sr0.4Ca0.6La4Ti5O17 which exhibited, epsilon(r) similar to 53.7, Qf(o) similar to 11,532 GHz and T-f similar to 1.4 ppm/degrees C. (C) 2011 Elsevier Ltd. All rights reserved.