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- MakaleAçık Erişim2025Scopus SJRQ1Soil Permittivity Extraction by Time-Domain Free-Space Calibration-Free Microwave Measurements With No Thickness Information
Hasar, Ugur Cem; Korkmaz, Huseyin; Kaya, Yunus; Iliev, Teodor
An attractive microwave free-space method is proposed for permittivity extraction of soil samples using calibration-free time-domain measurements. Different from other similar methods in the literature which use the layer-stripping approach in the forward direction in the extraction process, its formalism is based on the layer-stripping approach in the backward direction, whereby allowing extraction of permittivity from interfacial reflection coefficient only without resorting to any thickness information, especially useful for time-domain analysis of multilayer structures having multiple reflection terms. Effects of angle misalignment, loss, and surface roughness on the extraction performance of the proposed method (PM) are analyzed by numerical examples. Permittivity measurements of three low-loss flat solid samples [polypropylene (PP), polyethylene (PE), and polyoxymethylene (POM)] were first performed by a free-space setup operating over 1–18-GHz frequency range to validate our methodology and compare its accuracy against other similar methods in the literature. Thereafter, permittivity measurements of two soil samples sieved with similar and different sizes (coarse- and fine-grained soil samples) by the same free-space setup were then considered to assess the applicability and performance of our method for electromagnetic property analysis of homogeneous and partially inhomogeneous soil samples.
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İncele - MakaleAçık Erişim2022Scopus SJRQ1Broadband Soil Permittivity Measurements Using a Novel De-Embedding Line-Line Method
Hasar, Hafize; Hasar, Ugur C.; Kaya, Yunus; Oztas, Taskin; Canbolat, Mustafa Y.; Aslan, Nevzat; Ertugrul, Mehmet; Ramahi, Omar M.
A new de-embedding line-line method has been proposed for accurate complex relative permittivity ( ε ᵣ ) determination of soil samples loaded into an EIA 1-5/8' coaxial transmission line measurement system. The method has three main features. First, it bypasses the requirement of calibration of this system by using only two identical coaxial lines with different lengths. Second, it does not need any numerical technique for ε ᵣ determination. Third, it does not require knowledge of electromagnetic properties and thickness information of the bead used for supporting soil samples. The method is next validated by simulations performed using a full 3-D electromagnetic simulation program (CST Microwave Studio) and by ε ᵣ measurement of a polyethylene (PE) material. Finally, ε ᵣ values of three air-dried and water-saturated soil samples having 90% or more sand content with different electrical conductivities (ECs) and gathered from different areas of the city Gaziantep in Turkey, were measured.
AtıfScopus18WoS16OpenAlex16İncele