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- MakaleAçık Erişim2026Scopus SJRQ1Permittivity Extraction of Electrically Thin Samples by Reflection-Only Free-Space Measurements
Hasar, Ugur C.; Xue, Bing; Ozturk, Hamdullah; Kaya, Yunus; Ozturk, Gokhan
A permittivity extraction procedure is devised for electrically thin samples from reflection-only free-space measurements. Unlike previous studies, this procedure relies on sample-back metal termination measurements especially useful for thinner samples. An objective function independent of antenna transmission characteristics and reference plane position is derived. Minimum and maximum thickness and permittivity values for which our method is applicable are also examined. Free-space measurements at X-band (8.2-12.4 GHz) of a Rogers 4350B sample (approx 1.52 mm) and a FR4 sample (1.60 mm) were performed to validate our method with a dielectric constant less than 5% variation.
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İncele - 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.
AtıfScopus41WoS37OpenAlex35İncele - MakaleYalnız künye2021Scopus SJRQ1Graphical Method for Examining Complex Natural Frequencies of Dispersive Materials
Hasar, Ugur C.; Ozturk, Gokhan; Barroso, Joaquim J.; Gurbuz, Tolga U.; Kaya, Yunus; Ertugrul, Mehmet
A graphical method is extended to and applied for visual inspection of solution patterns (region of complex natural frequencies sₙ) in the complexs-plane for dispersive materials characterized by the Debye and Lorentz models. These patterns are in the form of exponential decay and C-shaped profiles for the Debye and Lorentz models, respectively. Their forms are observed to be affected (e.g., moving left/right) in different manners with a variation of dispersion parameters. This method, thanks to its visual inspection capability, can help in analyzing/synthesizing filters and frequency-selective surfaces.
AtıfScopus6WoS6OpenAlex7İncele