中文摘要：

采用传统固相合成法制备0.1La（Mg_（0.5）Ti_（0.5））O_3-（0.9-x）CaTiO_3-x（Li_（0.5）Sm_（0.5））TiO_3（LMT-CT-LST,摩尔比x=0.1~0.6）系列微波介质陶瓷,并研究该系列微波介质陶瓷的物相结构、表面形貌及微波介电性能。X线衍射（XRD）研究表明,所有的LMT-CT-LST样品均为钙钛矿结构。扫描电镜（SEM）表明,随着（Li_（0.5）Sm_（0.5））TiO_3含量的增加,样品的晶粒尺寸会不断增加。当x=0.6时,有些晶粒会出现异常长大现象,这对样品的微波介电性能有很大的影响。介电性能研究结果显示,随着（Li_（0.5）Sm_（0.5））TiO_3含量从0.1增加至0.6,介电常数（εr）略微从121.56减小至117.5,而对应的品质因数（Q×f）从10 055.71GHz降低至4 042.15GHz;此外,该体系谐振频率温度系数（τf）随（Li_（0.5）Sm_（0.5））TiO_3含量的增加逐渐向负值方向移动。当x=0.6时,复合陶瓷在1 340℃烧结4h,可获得最佳的综合微波介电性能,即ε_r≈117.5,Q×f≈4 042.15GHz（f=3.415 GHz）,τ_f≈10.13×10-6/℃。

英文摘要：

The 0.1 La（Mg_（0.5） Ti_（0.5））O3-（0.9-x）CaTiO_3-x（Li_（0.5） Sm_（0.5））TiO_3（LMT-CT-LST,x=0.1~0.6）ceramics were prepared by the conventional solid-state reaction process.The phase composition,microstructures and microwave dielectric properties of the multiphase ceramics were investigated.The XRD results suggest that a single perovskite structure were formed for the LMT-CT-LST ceramics.The SEM result showed that the grain sizes of the sample were increased with the increase of（Li_（0.5） Sm_（0.5））TiO_3 content.At x= 0.6,the grains were appeared abnormal phenomenon,it has a great influence on the microwave dielectric properties of the samples.After adding（Li_（0.5） Sm_（0.5））TiO_3 content into the system,the permittivity（εr）slightly decreased from 121.56 to 117.5 when xvaried from 0.1 to 0.6.Mean while,the corresponding quality factor（Q×f）observably decreased from 10 055.71 GHz to 4 042.15 GHz.In addition,the temperature coefficient of resonant frequency（τf）was gradually shifted to the negative direction with the increase of（Li_（0.5） Sm_（0.5））TiO_3.The LMT-CT-LST ceramics with x=0.6,sintered at1 340 ℃ for 4 h,showed the excellent microwave dielectric properties of permittivityεr≈117.5,quality factor Q×f≈4 042.15 GHz（f=3.415 GHz）and a almost near-zero temperature coefficient of resonant frequencyτf≈10.13×10-6/℃.