Study On Modification Of CAS/YMAS-based Microwave Dielectric Ceramics

With the advent of the Internet of Things,5G communication,and multi-channel communication technologies,people have higher demands on the transmission speed and quality of signals,which makes the demand for microwave dielectric ceramic materials more urgent.In particular,ceramic materials with low dielectric constant and high quality factor and adjustable temperature coefficient of temperature have become hot research fields.In this paper,Ca₂Al₂SiO₇?CAS?ceramics,Y_2.9R_0.1MgAl₃SiO₁₂?R=Lu,Y,Dy,Eu,Sm?ceramics,?1-x?Y₃MgAl₃SiO₁₂-xTiO₂?x=0,0.03,0.06,0.09,0.2?ceramic with low dielectric constant were prepared by solid-state reaction method.?1?Ca₂Al₂SiO₇ ceramic is prepared by solid-state reaction method.XRD analysis indicated that the ceramic was a single phase ceramic.The Rietveld structure refinement indicates that the ceramic belongs to the tetragonal system,and the five-membered ring structure is composed of AlO₄ and?Si/Al?O₄ tetrahedron.The Ca atom and the surrounding oxygen atoms constitute an octa-coordinate polyhedral structure.Density is a major factor affecting the dielectric properties of microwaves.The variable temperature Raman and the variable temperature XRD indicate that the ceramic has a Curie temperature point higher than 900?.The best microwave dielectric properties were obtained at a sintering temperature of 1440?:?r=8.86,Q×f=22457 GHz,?f=-51.06 ppm/?.?2?Y_2.9R_0.1MgAl₃SiO₁₂?R=Lu,Y,Dy,Eu,Sm?ceramic was prepared by solid-state reaction method.The effects of ionic radius on the phase composition,crystal structure and dielectric properties of Y3MgAl₃SiO₁₂ ceramics were investigated.XRD analysis showed that the prepared samples were all single-phase ceramics,and the diffraction peaks matched with PDF#33-0040,which belonged to the cubic system.When the ionic radius of the doping is closest to the Y³⁺ionic radius,Y_2.9Dy_0.1MgAl₃SiO₁₂ ceramics obtains the best microwave dielectric properties at 1525?:?r=9.4,Q×f=63796 GHz,?f=-35.8 ppm/?.?3?The?1-x?Y₃MgAl₃SiO₁₂-xTiO₂?x=0,0.03,0.06,0.09,0.2?ceramics were prepared by solid-state reaction method.The effects of different amounts of TiO₂ on the microwave dielectric properties of Y₃MgAl₃SiOi2 ceramics were investigated.XRD analysis showed that the phase of TiO₂ and Y2Ti₂O₇ was produced as the amount of TiO₂ added increased.As the amount of TiO₂ increases,the sintering temperature can be lowered,the sintering range can be reduced,the dielectric constant can be increased,and the frequency temperature coefficient can be moved in a positive direction.At x=0.2,0.8Y₃MgAl₃5iO₁₂-0.2TiO₂ ceramics obtained the best microwave dielectric properties at 1450?:?r=11.7,Q×f=21054 GHz,?f=+5.23 ppm/?.