MICROWAVE PROPERTIES OF CERAMIC NONLINEAR DIELECTRICS
STANFORD UNIV CA MICROWAVE LAB
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This investigation was undertaken to develop and apply new measurement techniques for obtaining the small-signal and large-signal microwave characteristics of ceramic nonlinear dielectrics. A transmission method for measuring the smallsignal complex dielectric constant was derived and is described in detail. Measurements were made on representative ceramics in the X-band frequency range, and the results are given as curves of the real part of the relative dielectric constant and of the loss tangent as functions of temperature with dc bias levels up to 32 kvcm. An experimental curve of the relative dielectric constant of a 73 barium titanate27 strontium titanate ceramic was obtained for the frequency range of 3 kmc to 270 kmc. A curve showing the per cent change of the relative dielectric constant over the temperature range from 95 F to 123 F the Curie temperature is approximately 72 F was also obtained. The large-signal microwave characteristics of a nonlinear dielectric were measured at 3 kmc by using a re-entrant coaxial cavity in which a cylindrical post of the ceramic was placed in the region of high electric field intensity.
- Electricity and Magnetism