The La(Mg_(0.5-x)Sr_xSn_(0.5))O_3 ceramics contained La_2Sn_2O_7. An apparent density of 6.56 g/cm~3, a dielectric constant (ε_r) of 20.5, a quality factor (Q × f) of 107,900 GHz, and a temperature coefficient of resonant frequency (τ_f) of-84 ppm/°C were obtained...