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Frequency‐Dependent Qf Value of Microwave Dielectric Ceramics
Author(s) -
Li Lei,
Chen Xiang Ming
Publication year - 2014
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.13199
Subject(s) - dielectric , microwave , ceramic , materials science , microwave cavity , dielectric loss , range (aeronautics) , resonant cavity , permittivity , analytical chemistry (journal) , chemistry , optics , composite material , optoelectronics , telecommunications , physics , laser , chromatography , computer science
The microwave dielectric properties of some typical low‐loss dielectric ceramics (CaNdAlO 4 , Ba(Mg 1/3 Nb 2/3 )O 3 , Ba(Zn 1/3 Nb 2/3 )O 3 , Ba 4 Sm 9.33 Ti 18 O 54 , Ca 0.71 Nd 0.26 TiO 3 and SrTiO 3 ) were evaluated at different frequencies by using high‐order TE 0np resonant modes of resonant cavity method. The dielectric constant shows little dependence on frequency for these microwave dielectric ceramics, while the Qf value increases with frequency in the measurement frequency range of 3–14 GHz. The results indicate that the Qf value as a frequency‐independent constant at microwave frequencies is not valid for these microwave dielectric ceramics, while the constant Qf value has been accepted as a common recognition for a long period. The frequency dependence of Qf value is attributed to the defects‐induced extrinsic dielectric loss, which cannot be avoided in actual microwave dielectric ceramics.