The Sr-Gehlenite (Sr2Al2SiO7) ceramic has been prepared by the conventional solid-state ceramic route. Phase pure Sr2Al2SiO7 (SAS) ceramic sintered at 1525 degrees C for 4 h has epsilon(r) = 7.2 and Q(u) x f = 33,000 GHz. The SAS showed large negative tau(f) of -37.0 ppm/degrees C. A low value of tau(f) was achieved by preparing SAS-CaTiO3 composite. The composite with 0.04 volume fractions (V-f)CaTiO3 sintered at 1500 degrees C for 4 h showed good microwave dielectric properties: epsilon(r) = 8.6, Q(u) x f = 20,400 GHz and tau(f) = +8.5 ppm/degrees C. (C) 2012 Elsevier B.V. All rights reserved.