Improved Non-Linear Dielectrics for Electronic Tuning.
ARMY ELECTRONICS COMMAND FORT MONMOUTH N J
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NG INFLUENCE OF THE GRAIN SIZE OF BARIUM STRONTIUM TITANATE ON THE PERMITTIVITY RATIO, THE VARIATION OF PERMITTIVITY WITH SUPERIMPOSED DC BIAS, IS PRESENTED AS A FUNCTION OF TEMPERATURE. A 10-fold decrease in permittivity with 80 vmil dc bias was obtained at the Curie temperature of a ceramic with coarse grains. The mechanisms responsible for the field dependent change in permittivity, namely a field induced paraelectric to ferroelectric transition and a domain alignment process, are re-examined in the light of recent findings stressing the influence of microstructure. The frequency response of dissipation factor is also included along with the proposed mechanisms that account for the observed behavior. Satisfactory performance of the non-linear dielectrics in tuning devices is possible within a constant temperature environment and a frequency range of 3 to 30 MHz. Author
- Electrical and Electronic Equipment
- Ceramics, Refractories and Glass