Broadband permittivity measurement of liquids in a semi-open coaxial test cell with meniscus-effect removal

We study how surface distortions of liquid samples due to a meniscus and a tilt of a semi-open coaxial test cell affect errors in a broadband permittivity determination. The study is based on the scattering parameters, obtained using the electromagnetic simulations of samples with flat and distorted surfaces in a broad frequency range up to 18 GHz. The parameters are processed with the classic Nicolson–Ross–Weir (NRW) method and our new meniscus removal technique. We analyze the errors for several samples of different properties, such as distilled water and propan-2-ol. The results show that the meniscus removal technique is more robust and provides smaller errors in the permittivity determination compared to the classic NRW method. The effect of the cell tilt, to our best knowledge, has not been considered in the literature yet.

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“…The length of the empty cell l a0 , needed in (6), is usually known from the mechanical or electrical measurements [28].…”

Section: Measurement Proceduresmentioning

confidence: 99%

Errors in Broadband Permittivity Determination Due to Liquid Surface Distortions in Semi-Open Test Cell

Kalisiak

Wiatr

2021

Remote Sensing

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“…Thus, boldTf()0 is utilized as in [11,12] to remove boldTb from (2) and extract components representing a k -th state of the test c ell itself Tck=TakTsk=TfkTf0−1Ta00.277778em.…”

Section: Theorymentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Kalisiak¹,

Wiatr²

2019

Sensors

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We present a new technique for broadband liquid characterization using a semi-open, vertically oriented test cell that is measured with a calibrated vector network analyzer in three states: the empty one and filled with two different volumes of the liquid under test. Using the measurements, we de-embed a transfer matrix representing a volume increment of the liquid sample and determine its column height with a novel closed-form formula. Thanks to the de-embedding, the method enables one, for the first time, to completely remove effects caused by a reproducible meniscus forming the top surface of a liquid tested in the cell and determine not only the propagation constant, but also characteristic impedance of the liquid sample, from which its permittivity and permeability are calculated. The results are highly consistent, because all the measurements are performed without disassembling the cell. We validate experimental results of the meniscus removal method by comparing them with reference data and outcomes of the Nicolson–Ross–Weir method.

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

Kalisiak

Wiatr

2018

2018 12th International Conference on Electromagnetic Wave Interaction With Water and Moist Substances (ISEMA)

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Broadband permittivity measurement of liquids in a semi-open coaxial test cell with meniscus-effect removal

Cited by 3 publications

References 9 publications

Errors in Broadband Permittivity Determination Due to Liquid Surface Distortions in Semi-Open Test Cell

Errors in Broadband Permittivity Determination Due to Liquid Surface Distortions in Semi-Open Test Cell

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

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

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