Continuum properties from interdigital electrode dielectrometry

Using a modal approach, a model is derived that makes the interdigital electrode microdielectrometer developed by S. D. Senturia et al. (J. Adhesion, vol.15, p.69-90, 1982) applicable to measuring continuum parameters in a wide range of heterogeneous media. In this so-called imposed omega -k technique, the medium is excited at the temporal (angular) frequency omega by means of an interdigital electrode structure having a spatial periodicity length lambda =2 pi /k and hence a dominant wavenumber k. Given the surface capacitance density C( omega , k) of any linear system having property gradients perpendicular to the plane of the electrodes, the model predicts the complex gain, taking into account the properties, geometry, and terminal configuration of the interdigital electrode structure. This capability can then be used with an appropriate parameter estimation strategy to determine the continuum properties and/or geometry of the medium. Examples illustrating the application of the technique are presented.<>