Experimental Study of Meniscus Effect on Broadband Permittivity Measurements of Liquids in a Semi-Open Coaxial Test Cell

Complete Meniscus Removal Method for Broadband Liquid Characterization in a Semi-Open Coaxial Test Cell

“…The issue of meniscus has been recently addressed in [12,13] where a more advanced technique than [11] has been introduced. Instead of two, this new technique exploits three measurement states, i.e., the empty-cell state and the other two with different volumes of liquid.…”

“…However, the heights of liquid columns, necessary to this end, were still determined with the Somlo’s method [3], i.e., without considering the meniscus. A search [13] on meniscus effects in the permittivity measurements of distilled water samples, performed up to 18 GHz in a 7 mm line-standard test cell, showed that the errors caused by meniscus are rather small. Unfortunately, finite residual errors of the VNA calibration impeded discerning them in the de-embedded scattering parameters of the samples or in the column height determination.…”

“…Unfortunately, finite residual errors of the VNA calibration impeded discerning them in the de-embedded scattering parameters of the samples or in the column height determination. However, comparisons of the permittivity results calculated with different methods demonstrated evident advantages of this new three-state technique [12,13]. Nevertheless, one may expect that meniscus may have a stronger influence on accuracy of such permittivity measurements at higher frequencies when wave guiding structures of smaller size are required.…”