Accession Number : AD0765417

Title :   Improved Non-Linear Dielectrics for Electronic Tuning.

Descriptive Note : Technical rept.,

Corporate Author : ARMY ELECTRONICS COMMAND FORT MONMOUTH N J

Personal Author(s) : Wichansky,Howard

Report Date : AUG 1973

Pagination or Media Count : 36

Abstract : 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 v/mil 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)

Descriptors :   (*TUNING DEVICES, *FERROELECTRIC CRYSTALS), (*VARIABLE CAPACITORS, VERY HIGH FREQUENCY), BARIUM COMPOUNDS, STRONTIUM COMPOUNDS, TITANATES, MICROSTRUCTURE, NONLINEAR SYSTEMS, SINTERING, CERAMIC MATERIALS, DISSIPATION FACTOR

Subject Categories : Electrical and Electronic Equipment
      Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE