Resumo

GUADARRAMA-SANTANA, A.  e  GARCIA-VALENZUELA, A.. Non-destructive measurement of the dielectric constant of solid samples. Rev. mex. fis. [online]. 2009, vol.55, n.6, pp.477-485. ISSN 0035-001X.

We discuss and analyze a practical methodology for the determination of the dielectric constant of a macroscopic solid sample in a nondestructive way. The technique consists in measuring the capacitance between a pointer electrode and the dielectric surface as a function of the separation distance in a scale comparable to the radius of curvature of the tip's apex. The changes in capacitance that must be measured will commonly be in the atto-farad scale and require specialized instrumentation which we also describe here. The technique requires two calibration standards and the sample needs to have a portion of its surface flat and some minimum dimensions, but otherwise it can have an arbitrary shape. We used a simple model based on the method of images to explain the methodology and present experimental results with the proposed methodology.

Palavras-chave : Capacitance measurements; dielectric constant; pointer electrode; materials characterization.

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