新型等磁介、低损耗材料频段差异化设计机理及制备方法研究

Antenna is the important part of a wireless communication system. With the miniaturization development of wireless communication system,it is a bottleneck problem to reduce the characteristic size of antennas without affecting their performances. The new magneto-dielectric materials with matched permeability and permittivity have very prominent advantages in miniaturization and high performance antennas. However, till now this kind of materials reported not only cover a narrow frequency band,but also lack of researchs on band differentiated design mechanism and preparation method. So in this project, we will first divide the magneto-dielectric materials into four types based on their frequency characteristics. After that, we will investigate the composition design mechanism and laws based on the theoretical analyses and practices. Then we will deeply study the influences of preparation processes, doping and compositing program on the microstructures and magneto-dielectric properties of the materials. And the methods of adjusting magnetic and dielectric spectrum characteristics and reducing their magnetic and dielectric losses will be investigated. Finally, based on the produced magneto-dielectric materials, we will design and develop several antennas and compare their properties with the antennas produced by the traditional high dielectric materials. Through analyzing the properties of antennas, we can confirm the feasibility and availability of the materials, and establish some theoretical and practical foundations for the development of the new kind magneto-dielectric materials used between 1MHz ~ 2GHz.

天线是无线通信系统的重要组成部分，如何在保证天线效能的基础上减小其特征尺寸，成为当前无线通信系统小型化发展迫切需要解决的瓶颈难题。新型等磁介、低损耗材料在实现天线的小型化和高性能方面具有十分突出的优势，但目前报道的该类材料不仅覆盖频域窄，而且缺乏系统性频段差异化设计机理及制备方法的研究。为此，本课题首先根据频域特性将等磁介材料划分为四大类，分别结合材料设计理论和实践探索，掌握影响其磁、介谱特性的配方设计机理和规律；其次，系统研究材料制备工艺方法及掺杂、复合方案对材料体系微观形貌、晶相组成和磁介性能的综合影响，探寻可控调节材料磁介谱特性并降低磁、介损耗的有效途径。最后，基于研制的等磁介材料进行多种天线的设计与研制，并与同类高介材料制备天线进行综合对比，验证等磁介材料在天线中的应用效能，为实现覆盖1MHz~2GHz超宽频带等磁介材料奠定理论和实践基础。

本项目针对系列化的等磁介、低损耗磁介材料的设计、研制及在天线中的应用开展了系统深入的研究，取得主要研究进展包括：明确了对于3MHz~30MHz的超低频段范围内，等磁介材料主要采用NiCuZn与BaTiO3复合的方式来实现。成功研制出一款在3~30MHz频率范围内磁导率和介电常数都约为29，且磁损耗正切小于0.02，介电损耗正切小于0.002的高性能等磁介材料；采用二步烧结法开展了单相NiCuZn铁氧体等磁介材料的研究，通过抑制晶界迁移并促进晶界扩散的方式实现了铁氧体均匀、细晶粒和高致密的微观结构，成功研制出一种磁导率和介电常数约为11.8，在10~100MHz频率范围内磁损耗和介电损耗正切都低于0.015的等磁介材料；在30~300MHz频段范围内，主要采用单相Co2Z型铁氧体材料来实现等磁介特性的材料设计与研制方案。通过优化掺杂及工艺方案，成功实现了一种在30-300MHz频率范围内，磁导率约为14，磁损耗正切低于0.05，介电常数约为15，介电损耗正切低于0.002的等磁介材料；为进一步拓展磁介材料的适用频段，我们以Co2Z铁氧体材料为母体，研究了铝替代铁和掺杂BBSZ玻璃等方案对降低材料体系高频损耗的影响，同时还尝试了Co2Z铁氧体材料与有机介质材料复合的方案，均取得了不错的效果；基于研发的各种磁介材料，设计并试制出了多款分别应用于30MHz、200MHz以及915MHz的多款小型化磁介基板天线，很好的验证了研制磁介材料的应用效能。. 项目相关研究共发表SCI期刊论文35篇，申请国家发明专利11项，其中3项已获授权。出版著作1部，并获得教育部科技进步二等奖、中国电子学会科技进步二等奖以及四川省科技进步三等奖各一项。