Use of Two Open-Terminated Coaxial Transmission-Lines Technique to Extract the Material Relative Intrinsic Parameters

Abstract

We have presented an open-terminated transmission-line technique, based on the use of two substantially identical circular coaxial structures with different lengths, to extract the material relative permittivity $\varepsilon _{r}$ . All data acquisitions obtained from experimental measurements have been done at the entry of the connector-input source interface. The technique is well-utilized despite the test cell discontinuity, and it met the goal of extracting the relative intrinsic parameters with good accuracy. The technique improvement found its advantage in the scan of a large frequency range by introducing a new concept based upon the sum of the lengths of identical fixtures and the backward wave propagation. High order-modes propagation that restricts the frequency range in the transmission configuration is not a limit in this new technique. Otherwise, the measurement methodology, grounded in the principle of the automatic correction coefficient determination, is done to achieve the aim. Easily filling up the test cell with the sample to characterize, we validated the new broadband technique in [1.5 – 15] GHz by using insulators like Aquarium sand, wheat semolina, and raffia (vinifera and laurentiis varieties). From the use of the same fixture, result comparisons have been done with those from the two-line technique.