Ultralow loss polycrystalline alumina
2002; American Institute of Physics; Volume: 81; Issue: 26 Linguagem: Inglês
10.1063/1.1532553
ISSN1520-8842
AutoresJonathan Breeze, Xavi Aupi, Neil McN. Alford,
Tópico(s)Acoustic Wave Resonator Technologies
ResumoPolycrystalline 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.
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