Structural features and microwave dielectric properties of (Sr0.2Ca0.488Nd0.208)Ti1-xGa4x/3O3 (SCNTGx, 0.2 <= x <= 0.6) samples were studied. The X-ray patterns revealed that a single phase with orthorhombic perovskite-like structure was obtained in the range of x= 0.2-0.4. A certain amount of Ga2O3 phase was detected at x= 0.5 from the XRD data. However, some unknown phase was formed as a secondary phase when x increased up to 0.6. Moreover, as Ga3+ concentration increased, the epsilon(r) decreased due to the smaller ionic polarization of Ga3+ than that of Ti4+, the Q x f value increased firstly and then decreased because of the existence of the unknown secondary phase. And the tau(f) values changed from a positive to negative value, arising from a reduction in tolerance factor (t) for tilted region (t< 1) in perovskite structure. Furthermore, an extra Raman band centered at about 240/236 cm(-1) was detected in SCNTGx ceramics at x=0.5, 0.6, which was caused by the appearance of the Ga2O3 phase. The SCNTGx (x=0.5) ceramic sintered at 1350 degrees C for 4 h showed good microwave dielectric properties with epsilon(r)= 43.7, Q x f = 60,100 GHz (at 4.71 GHz) and tau(f)= 8.3 ppm/ degrees C. Obviously, the introduction of Ga2O3 could efficiently improve Q x f value of the SCNTGx specimens. (C) 2015 Elsevier Ltd. All rights reserved.