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    Broadband Soil Permittivity Measurements Using a Novel De-Embedding Line-Line Method
    (IEEE-Inst Electrical Electronics Engineers Inc, 2022) Hasar, Hafize; Hasar, Ugur C.; Kaya, Yunus; Oztas, Taskin; Canbolat, Mustafa Y.; Aslan, Nevzat; Ertugrul, Mehmet
    A new de-embedding line-line method has been proposed for accurate complex relative permittivity (epsilon(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 epsilon(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 epsilon(r) measurement of a polyethylene (PE) material. Finally, epsilon(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.
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    Honey-Water Content Analysis by Mixing Models Using a Self-Calibrating Microwave Method
    (IEEE-Inst Electrical Electronics Engineers Inc, 2023) Hasar, Hafize; Hasar, Ugur C.; Kaya, Yunus; Ozturk, Hamdullah; Izginli, Mucahit; Oztas, Taskin; Aslan, Nevzat
    Microwave techniques, as an indirect approach, can be applied for analyzing water content in honey by way of permittivity measurements. However, these techniques require proper calibration to accurately perform such indirect evaluation. Improper calibration standards used in this calibration process could naturally result in a reduction in the accuracy and thus the performance of dielectric characterization using microwaves. Self-calibrating microwave techniques can reduce the effects of imprecise standards and thus improve the performance of microwave measurements by bypassing the requirement of calibration standards. In this study, we develop a self-calibrating microwave measurement technique to determine the relative permittivity of honey samples and implement binary mixing models to predict adulteration levels of water-adulterated honey. From this implementation, it is observed that the parallel-capacitance mixing model could efficiently be applied to determine the concentration of water adulteration by examining the differences between absolute values of the real parts of the measured and predicted complex permittivities of adulterated honey.
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    Prediction of water-adulteration within honey by air-line de-embedding waveguide measurements
    (Elsevier Sci Ltd, 2021) Hasar, Hafize; Hasar, Ugur Cem; Kaya, Yunus; Ozturk, Hamdullah; Izginli, Mucahit; Ozbek, Ibrahim Yucel; Oztas, Taskin
    An efficient de-embedding air-line microwave method has been proposed for accurate relative complex permittivity, epsilon(r) = epsilon(r)' - i epsilon(r)'', measurement of water-adulteration level within honey. It could be effectively applied to eliminate the errors arising from usage of imperfect calibration standards because it bypasses the requirement of these standards. Its accuracy is improved by utilizing the unitary and similarity properties of a passive two-port network, and then is compared with the accuracy of a calibration-dependent method present in the literature by using normalized root-mean-square-error (N-RMSE) values of epsilon(r)' and epsilon(r)'' of distilled water, in reference to the Debye value. From this comparison, it is observed that N-RMSE values calculated for epsilon(r)' (and epsilon(r)'') by using this calibration-dependent method and the (improved) proposed method are, respectively, around 0.1955 (0.1002) and 0.1962 (1.1067), indicating a good agreement between them. After validation the proposed de-embedding method using distilled water measurements, tested pure honey was adulterated with distilled water by different percentage values delta ranging from 1% to 10% in 1% increments. It is observed that the maximum distance between extracted epsilon(r)' (or epsilon(r)'') values of adulterated honey by the applied calibration-dependent method and the proposed method is less than 2%. Afterward, an empirical formula was devised to fit epsilon(r)' and epsilon(r)'' values from measured epsilon(r) of water-adulterated honey with various delta levels. It is noted that extracted epsilon(r)' is much more better fitted than extracted epsilon(r)'', especially for delta <= 4. Next, an optimization process is followed to evaluate the frequency for optimum prediction of adulteration levels using the empirical formula based on epsilon(r)' or epsilon(r)'' It is noticed that optimized delta values using the empirical formula based on epsilon(r)' (with an average prediction error of around 0.071 at 4.5 GHz) are superior to optimized delta values using the empirical formula based on epsilon(r)'' (with an average prediction error of around 0.085 at 4.2 GHz) for prediction of previously known delta values. Sensitivity and uncertainty analyses were performed to assess and improve the accuracy of the proposed method.