石榴石型低介电常数微波介质材料的谐振频率温度系数与介电损耗调控机制研究

随着5G无线通信系统、物联网、卫星和智能传输系统的迅猛发展，低介电常数和高品质因数的微波介质材料逐渐成为研究与开发的热点。在阳离子组成与占位设计的基础上，制备系列A位、B位填满或未填满、有序-无序等不同类型的石榴石型陶瓷，系统开展结构（晶体结构、电子结构与微结构、相变特性）、晶格振动特性与介电性能研究，探讨其不同结构（氧八面体、四面体与十二面体变形、离子成键特性、离子有序类型与有序度等）对性能（尤其是介电损耗与谐振频率温度系数）的影响规律及机制，进而有效指导石榴石型微波介质材料新体系的选择与性能优化，同时为揭示含四面体的低介电常数微波介质材料的构效关系及性能调控的机理打下基础。

To meet the recent rapid progress in fifth generation wireless systems, the internet of things (IoT), satellite broadcasting and intelligent transport systems (ITS), low εr and low-loss microwave dielectric materials have been intensively investigated. In this project, based on crystal structure of garnet, the cation compositions and occupation are firstly designed. Then, a series of filled/unfilled, order/disorder garnets ceramics will be synthesized and prepared, and their structure including microstructure, crystal structure, electronic structure as well as phase transition, lattice vibrational spectra and dielectric properties are systematically investigated. The effect and mechanism of different dodecahedron，octahedron and tetrahedron structures, chemical bond and order-disoder on dielectric properties (especially dielectric loss and temperature coefficient of resonant frequency) will be discussed. These studies will provide theoretical and experimental basis for the selection and properties optimization of novel low εr and low-loss microwave dielectrics materials with garnet structure, which also do help to explore the relationship between structure and properties of tetrahedral containing microwave dielectric materials with low εr.