低介微波介质陶瓷基板材料研究进展

Investigating Progress on Low-Permittivity Microwave Dielectric Ceramic Substrate

低介电常数能减小基板与电极之间的交互耦合损耗并提高电信号的传输速率,高品质因数有利于提高器件工作频率的可选择性和简化散热结构设计,近零的谐振频率温度系数有助于提高器件的频率温度稳定特性。特别在工作频率逐渐提高的情况下,介电损耗不断增大,器件发热量迅速增加,材料的热导率成为一个需要重点考虑的因素。由于陶瓷材料的热导率是有机材料的20倍左右,因此,低介电常数微波介质陶瓷成为制备高性能基板的理想材料。此外,基板材料还需具备高强度和优越的表面/界面特性等综合性能。鉴于此,首先评述了介电常数小于15的低介微波介质陶瓷材料体系的研究进展情况,在此基础上,介绍了降低基板材料介电常数的方法和表面致密化措施,最后指出了在高性能低介微波介质陶瓷基板材料研制过程中面临的问题及今后的发展方向。

Low-permittivity （ εr ） can minimize cross-coupling loss between substrate and conductor and shorten the time for the electronic signal transition, and high quality factor （ Q @ f） can increase selectivity and simplify heat dispersing structure, moreover near-zero temperature coefficient of resonant frequency （＂rf） can ensure stability of the frequency a- gainst temperature change. Especially as working frequency gradually expands, thermal conductivity of substrate should be considered carefully due to an increase in dielectric loss and calorific value. Thermal conductivity of ceramics is about 20 times as that of organic matterials, therefore, low-permittivity microwave dielectric ceramics become promising materials for high-performance substrate applications. In addition, high strength and excellent surface/interface characteristics are also required. So an overview on low-permittivity microwave dielectric ceramics with ετ 〈 15 are present firstly, and then measures on reducing permittivity and increasing surface densification are introduced. Finally, some suggestions of investigating high-performance low-permittivity microwave dielectric ceramic substrates are also proposed.