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A permittivity measurement system for high frequency laboratories

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / The open-ended coaxial probe is revisited as a broadband measurement system for general
high frequency permittivity measurements. Three coaxial probes were developed
that are suited for the measurement of both liquids and solids. The components of a
permittivity measurement system were investigated and improvements were made to
the coaxial probe where needed. This includes the development of a full wave code
with great calculation time improvements without sacrificing accuracy. This code allows
measurements to be performed in a high frequency laboratory and the permittivity extracted
without any mentionable delay. A capacitance model that better describes the
impedance of an open-ended coaxial line is also suggested that can be used for real-time
permittivity extraction over a limited frequency range.
Calibration formed a vital part of the project and great time was spent developing a
TRL and a SOLT calibration set for the coaxial probe geometry. The combination of the
TRL and SOLT standards also allows measurement of the residual errors after calibration
and is used in an uncertainty analysis of the extracted permittivity.
Well known materials such as PTFE, PVC, methanol and water were measured to
test the probes. The measured dielectric constants are all within 3% of values quoted in
literature. The loss term of the samples are also in good agreement with the expected
Date12 1900
CreatorsMarais, Johannes Izak Frederik
ContributorsPalmer, K. D., University of Stellenbosch. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
PublisherStellenbosch : University of Stellenbosch
Source SetsSouth African National ETD Portal
Detected LanguageEnglish
Format7446248 bytes, application/pdf
RightsUniversity of Stellenbosch

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