Abstract
Developing a material with a temperature coefficient of the resonant frequency (TCF) of zero is probably the most difficult aspect of research into microwave dielectric ceramics. There are a host of high-quality-factor ( Q ) high-relative-permittivity (ε r ) materials whose TCF is far too high to be usable, notably TiO 2 (ε r = 104; Q = 14000 at 3GHz: TCF = +427 ppm K -1 ). The challenge is to find ways of tuning TCF while maintaining values of ε r and Q suitable for use in microwave components. This paper explains, in terms of octahedral tilting and ε r dilution, the tunability of TCF or, more precisely, the temperature coefficient of ε r in Ca and Sr titanate-based ceramics. Examples of the structural changes that occur during tuning are also shown.
Original language | American English |
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Journal | Philosophical Magazine |
Volume | A81 |
Issue number | 2 |
State | Published - 2001 |
EGS Disciplines
- Materials Science and Engineering