Movable short-circuit technique to extract the relative permittivity of materials from a coaxial cell

• Main Authors: M. G. Lountala, F. Moukanda Mbango, F. Ndagijimana, D. Lilonga-Boyenga
• Format: Article
• Language: English
• Published: JVE International 2019-12-01
• Series: Journal of Measurements in Engineering
• Subjects: discontinuity impacts; movable short-circuit; propagation constant; relative permittivity; transmission-line
• Online Access: https://www.jvejournals.com/article/20925
• ISSN: 2335-2124; 2424-4635

In recent years, industrial applications have been based on the use of intrinsic material properties that improve designs, processes, qualities and product controls. To get to those intrinsic parameters, various appropriate techniques are required. In this paper, a new technique has been developed and presented. It essentially puts the emphasis on the dielectric relative permittivity extraction from the principle of a movable short-circuit through the coaxial transmission-line cell. This technique is aimed at drastically reducing the discontinuity impacts at the interface feed line (connector) and ideal line, solving the phase constant frequency limit, stopping the constraints bound to the higher mode propagations and improving the accuracy level when the frequency range has increased. The technique is based on the use of the sum of two different lengths of the cell by removing the first value of the phase constant in the frequency range of interest when it is negative. This new technique can be easily implemented; its focus is not on iterative principles, but on the use of the constant propagation of a Quasi-TEM mode of the transmission-line. The bio-food industry (semolina), environmental field (palm tree) and building trade (aquarium sand) were used to test the validity of the technique in 2-20 GHz.