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- MakaleAçık Erişim2022Scopus SJRQ1Broadband, Stable, and Noniterative Dielectric Constant Measurement of Low-Loss Dielectric Slabs Using a Frequency-Domain Free-Space Method
Hasar, Ugur C.; Kaya, Yunus; Ozturk, Gokhan; Ertugrul, Mehmet; Korasli, Celal
A broadband, stable, and noniterative free-space method is proposed for dielectric constant ϵr′ determination of low-loss dielectric slabs from reflection-only measurements through simple calibration standards (reflect and air). It is applicable for dispersive samples and does not require thickness information. Simulations of nondisperive and dispersive samples are performed to validate our method. Dielectric constant measurements of polyethylene and polyoxymethylene samples (9-11 GHz) are carried out to examine the accuracy of our method.
AtıfScopus41WoS37OpenAlex35
İncele - MakaleAçık Erişim2021Scopus SJRQ1Parameter Retrieval of Samples on a Substrate from Reflection-Only Waveguide Measurements
Hasar, Ugur Cem; Ozturk, Hamdullah; Kaya, Yunus; Izginli, Mucahit; Ertugrul, Mehmet
A microwave method has been proposed for constitutive parameters' extraction of samples on a known substrate. The advantage of this method is that it relies on noniterative reflection-only (air-and metal-backed) scattering (S-) parameters so that it is a good candidate for the characterization of samples when only one-port measurements are available. It is validated by the X-band (8.2-12.4 GHz) waveguide S-parameter measurements. A sensitivity analysis is followed to evaluate and improve the performance of our method.
AtıfScopus5WoS5OpenAlex3İncele - MakaleAçık Erişim2018Scopus SJRQ1Self-Calibrating Noniterative Complex Permittivity Extraction of Thin Dielectric Samples
Hasar, Ugur Cem; Kaya, Yunus
A microwave method relying on uncalibrated scattering (S-) parameters is proposed to measure the complex permittivity (ϵr) of thin dielectric samples. It has the following two main advantages. First, it takes into account effect of the sample holder, used for holding the sample, especially important for thin sample electromagnetic property characterization. Second, it does not require any specific information about the location of the sample (and its holder) inside its measurement cell for ϵr extraction. For validation of our method, we applied a commercial three-dimensional electromagnetic simulation program-CST Microwave Studio-and the Lorentz dispersion model. Uncalibrated (as well as calibrated) S-parameter measurements were conducted to measure ϵr of a 0.7 mm thick polyethylene sample (the sample holder was a 5.18 mm thick PVC sample) by our method and other similar methods in the literature. From the comparison, we observed that while the accuracy of tested methods significantly changed with inaccurate knowledge of the sample position inside its cell, the accuracy of our method did not much alter.
AtıfScopus18WoS16OpenAlex18İncele