A new technique for modeling open-ended waveguide structures and its application to dielectric spectroscopy.

Description
Title: A new technique for modeling open-ended waveguide structures and its application to dielectric spectroscopy.
Authors: Sibbald, Christopher L.
Date: 1991
Abstract: A novel technique for modeling the aperture admittance of open-ended waveguide structures radiating into a homogeneous, lossy dielectric half-space is presented. This technique combines both analytical and numerical approaches to express the aperture admittance as rational function of frequency and the relative permittivity of the external medium. The coefficients of the rational approximation, which depend upon the geometry of the waveguide and aperture, are determined in a very convenient manner from a relatively small number of computed admittances. This computed data is obtained via a full-wave movement method solution and, hence, includes the effects of radiation and energy storage in the near-field and evanescent waveguide modes. The accuracy of the numerical method is demonstrated by comparison with measured values. The new technique is successfully applied to obtain a model for the open-ended coaxial line geometry. The new model has important applications in the field of dielectric spectroscopy. In addition to yielding accurate solutions for the aperture admittance of the line as a function of the permittivity of the external medium, the model yields a unique solution to the inverse problem and permits a rigorous sensitivity and uncertainty analysis.
URL: http://hdl.handle.net/10393/7808
http://dx.doi.org/10.20381/ruor-6977
CollectionTh├Ęses, 1910 - 2010 // Theses, 1910 - 2010
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