Measurement of low-permittivity materials based on a spectral-domain analysis for the open-ended coaxial probe

Author

De Langhe, Pascal ; Blomme, Krist ; Martens, Luc ; De Zutter, Daniël

Author_Institution

Lab. of Electromagn. & Acoust., Ghent Univ., Belgium

Volume

42

Issue

5

fYear

1993

fDate

10/1/1993 12:00:00 AM

Firstpage

879

Lastpage

886

Abstract

A new coaxial probe was designed to measure materials with a low dielectric constant at frequencies up to 1.5 GHz. Inconsistencies found while measuring samples of different thicknesses were solved by abandoning the model of Levine and Papas for the probe and developing a new model. Using the spectral-domain technique, a closed-form expression is obtained for the admittance of a hanged open-ended coaxial line radiating into a planar-stratified material backed by a metal plate. This new expression can be considered as a correction to the model of Levine and Papas. The model considers the dominant mode as well as the effect of higher order modes. With this new model measurements of low dielectric constant materials were performed together with a perturbation analysis of the influence of air gaps. Theory and measurements were found to be in good agreement

Keywords

coaxial cables; electric sensing devices; microwave measurement; permittivity measurement; probes; spectral-domain analysis; 1.5 GHz; air gaps; closed-form expression; correction; hanged open-ended coaxial line; low dielectric constant materials; low-permittivity materials; model; open-ended coaxial probe; perturbation analysis; planar-stratified material; probe admittance; spectral-domain analysis; Admittance; Closed-form solution; Coaxial components; Dielectric constant; Dielectric materials; Dielectric measurements; Frequency measurement; Inorganic materials; Probes; Thickness measurement;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.252521

Filename

252521