Structural Chemistry and Properties of Ceramic Microwave Dielectrics

本文主要研究了一系列钙钛矿电介质的结构与损耗性能之间的关系。虽然这些基于钽酸盐的氧化物具有所有微波陶瓷中最低的损耗，但其性能的优化需要仔细控制其化学，加工和结构有序程度。对其中一种体系进行的初步研究表明，通过引入选定的化学取代基，可以降低与内部畴边界相关的介电损耗。该提案描述了一系列旨在理解和解释这种效应的实验研究，并概述了改善其他petroskite介电材料损耗特性的新方法。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电材料结构的哪些方面对于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. ***