Structural Chemistry and Properties of Ceramic Microwave Dielectrics

Davies 9421184本方案中的研究集中在一系列钙钛矿介电材料的结构和损耗性能之间的关系。虽然这些钽酸盐基氧化物是所有微波陶瓷中损耗最低的，但要优化它们的性能，需要仔细控制它们的化学、工艺和结构有序度。对其中一个系统进行的初步研究表明，通过引入选定的化学取代基，可以降低与内部磁区边界相关的介电损耗。该提案描述了一系列旨在了解和解释这种影响的实验研究，并概述了改善其他石油滑石介电材料损耗性能的新方法。这项工作的许多方面都是与工业界的科学家密切合作进行的，这项研究的几个方面预计将对商业陶瓷谐振器系统的加工和生产产生直接影响。这项工作的目标是了解现有微波介质材料的结构中哪些方面对实现优化的电子性能至关重要，并利用这些晶体化学见解来提高其他氧化物系统的性能。***

Davies 9421184 The studies in this proposal focus on the relation between the structures and loss properties of a series of perovskite dielectrics. While these tantalate-based oxides have the lowest losses of all the microwave ceramics, optimization of their properties requires careful control of their chemistry, processing, and degree of structural order. Preliminary investigations made on one of these systems have indicated that the dielectric losses associated with internal domain boundaries can be reduced by introducing selected chemical substituents. The proposal describes a series of experimental studies designed to understand and explain this effect, and outlines new approaches for improving the loss properties of other petrovskite dielectrics. Many aspects of this work are being conducted in close collaboration with scientists from industry, and several aspects of this study are expected to have a direct impact on the processing and production commercial ceramic resonator systems. %%% The goals of this work are to understand what aspects of the structures of the existing microwave dielectric materials are critical in realizing an optimized electronic performance, and to use these crystal chemical insights to enhance the performance of other oxide systems. ***