Study On Preparation And Performance Of 5G Base Station Filter Microwave Dielectric Ceramics

The MgTiO₃-CaTiO₃ microwave dielectric ceramic material has excellent dielectric properties,and its abundant raw materials and low cost have attracted the attention of a large number of researchers.In this paper,the traditional solid-phase sintering method is used to prepare 0.95MgTiO₃-0.05CaTiO₃（95MCT）-based microwave dielectric ceramics,the sintering performance and dielectric performance of 0.95MgTiO₃-0.05CaTiO₃-based microwave dielectric ceramic materials have been improved through methods such as ion substitution,addition of modifiers,and addition of sintering aids.The specific research content and results are as follows:Firstly,the influence of Al₂O₃ doping on the sintering characteristics,microstructure,phase composition and dielectric properties of 95MCT ceramics was studied.The results show that the doping of Al₂O₃ increases the bulk density of95MCT ceramics.The bulk density of 95MCT first increases and then decreases with the content of Al₂O₃.The introduction of Al₂O₃ generates the Mg Al₂O₄ phase.The appearance of the Mg Al₂O₄ phase reduces the dielectric constant of the material,but improving the material quality factor.At the same time,the doping of Al₂O₃inhibits the formation of Mg Ti₂O₅ mesophase,and reducing the sintering temperature.When the doping amount of Al₂O₃ is 0.10 wt%,sintering at 1350℃for4h,the best performance was obtained asε_r=18.88,Q×f=62957 GHz（8 GHz）,t_f=-18.08 ppm/℃。Secondly,the influence of additive MnO₂ doped 95MCT ceramics was studied.The results show that the doping of MnO₂ increases the volume density of 95MCT microwave dielectric ceramics.The volume density of 95MCT ceramics first increases and then decreases with the increase of MnO₂ content.The introduction of MnO₂ generates no new phase in 95MCT microwave dielectric ceramics,it forms a solid solution with 95MCT.MnO₂ doping improves the quality factor of the material,increasing the dielectric constant of the material.The introduction of MnO₂reduces the sintering temperature of 95MCT and improves the dielectric properties effectively.When the doping amount of MnO₂ was 0.01wt%,sintering at 1350℃for4h,the best performance was obtained asε_r=19.47,Q×f=62480 GHz（8 GHz）,t_f=-22.14 ppm/℃。Thirdly,the effects of sintering aid SiO₂ were studied.The results show that SiO₂ doping increases the volume density of 95MCT ceramics.With the increase of SiO₂ content,the volume density of 95MCT firstly increases and then decreases.The maximum value is obtained when the doping amount is 2 wt%.The main crystalline phase of 95MCT ceramics after doping with SiO₂ is considered to be MgTiO₃ and CaTiO₃.Doping with SiO₂ can reduce the formation of Mg Ti₂O₅ phase to a certain extent.The introduction of SiO₂ can reduce the sintering temperature of95MCT ceramics.When the doping amount of SiO₂ was 2wt%,sintering at 1250℃for 4h,the best dielectric properties were obtained as:ε_r=19.04,Q×f=58189 GHz（8GHz）,t_f=-18.22 ppm/℃。Finally,the difference between alcohol phase processing and water phase processing was explored.The results show that different media for wet ball milling have no effect on the phase composition of 95MCT-0.1Al₂O₃-0.01MnO₂.The main crystalline phases are MgTiO₃ and CaTiO₃,and there is no intermediate phase Mg Ti₂O₅.The 95MCT-0.1Al₂O₃-0.01MnO₂ ceramics prepared under different wet ball milling media exhibits great differences in microscopic morphology.The samples prepared by water processing have a microcrystalline structure with larger crystalline size.while ethanol processing have obvious uniform grain structure.The best dielectric properties of the samples prepared by ethanol processing are Q×f=59480 GHz（8 GHz）,ε_r=19.11,t_f=-17.5278 ppm/℃.The best dielectric properties of the samples prepared by water processing are Q×f=55166 GHz（8GHz）,ε_r=20.34,t_f=-20.0463 ppm/℃。...