Ultralow loss polycrystalline alumina
| Autor: | Neil McN. Alford, Xavi Aupi, Jonathan Breeze |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Permittivity
Materials science Physics and Astronomy (miscellaneous) Physics::Optics Relative permittivity Dielectric Condensed Matter::Materials Science Condensed Matter::Superconductivity visual_art visual_art.visual_art_medium Dissipation factor Dielectric loss Grain boundary Crystallite Ceramic Composite material GeneralLiterature_REFERENCE(e.g. dictionaries encyclopedias glossaries) |
| Zdroj: | Applied Physics Letters. 81:5021-5023 |
| ISSN: | 1077-3118 0003-6951 |
| Popis: | Polycrystalline alumina with extremely low microwave dielectric loss is reported with properties analogous to a theoretical ensemble of randomly oriented, single crystal sapphire grains. By avoiding deleterious impurities and by careful control of microstructure, we show that grain boundaries in aluminum oxide have only a limited influence on the dielectric loss. A method of measuring the electric permittivity and loss tangent of low-loss microwave ceramic dielectrics is reported. The electrical parameters such as relative permittivity and loss tangent are extracted using the radial mode matching technique. The measured values for ultralow loss polycrystalline aluminum oxide agree well with theoretical values modelled on an ensemble of randomly oriented anisotropic single crystal sapphire grains. |
| Databáze: | OpenAIRE |
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