Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 7Citation - Scopus: 8Compact Wideband Tapered-Fed Printed Bow-Tie Antenna With Rectangular Edge Extension(John Wiley and Sons Inc., 2019) Bozdağ, Göksenin; Seçmen, MustafaIn this article, a wideband printed bow-tie antenna is designed entire band of GPS (L5), PCS, IMT-2000, Bluetooth, Wi-Fi, WiMAX bands, and the most of frequency range of UWB. Apart from the traditional designs, the proposed antenna includes tapered printed line with a feeding point patch and triangular bows with rectangular edge extensions, which makes the antenna more compact. The antenna realized at the frequency band of 1.49-9.5 GHz (more than 6.3:1 ratio bandwidth) has the dimensions of 122mmx56mm (0.61(0)x0.28(0)). According to measurement results, the realized gain varies between almost 1 and 6.5 dBi with 4.44dBi average, which are in good agreement with simulation results. Radiation patterns at the lower frequencies of operating band show dipole like radiation pattern with higher cross-pol discrimination levels while they degrade at the higher frequencies due to increase in gain.Other Citation - WoS: 2Citation - Scopus: 1Erratum To: Multi-Band Cpw Fed Mimo Antenna for Bluetooth, Wlan, and Wimax Applications(John Wiley and Sons Inc., 2017) Deste, İrem; Bozdağ, Göksenin; Kuştepeli, AlpIn the above-mentioned article, which appeared in Microwave and Optical Technology Letters, Volume 58#9, DOI 30001, the captions for Figure 1 and Figure 4 were published incorrectly. The corrections are shown below: Figure 1 Element antenna (a) Geometry (b) Fabricated (a = 12.5 mm, b = m = v = o = 0.5 mm, c = 4 mm, d = n = 15 mm, e = h = 3 mm, f = 14 mm, g = 16 mm, i = 7 mm, k = 1.5 mm, l = 12 mm, p = 1.25 mm, r = 1.64 mm, s = 1.7 mm, t = 1.94 mm, u = 11.1 mm, w = 0.3 mm). [Color figure can be viewed at wileyonlinelibrary.com] Figure 4 Fabricated MIMO antenna (d1 = d3 = 7 mm, d2 = 10 mm, d4 = 12 mm). [Color figure can be viewed at wileyonlinelibrary.com] In addition, Figure 6 was published with an error. The corrected figure is shown below: The publisher regrets any confusion caused by these errors. (Figure presented.).Other Citation - WoS: 1Erratum: Wideband Planar Monopole Antennas for Gps/Wlan and X-Band Applications (microwave and Optical Technology Letters 58:2)(John Wiley and Sons Inc., 2016) Bozdağ, Göksenin; Kuştepeli, AlpArticle Citation - WoS: 5Citation - Scopus: 9Wideband Planar Monopole Antennas for Gps/Wlan and X-Band Applications(John Wiley and Sons Inc., 2016) Bozdağ, Göksenin; Kuştepeli, AlpIn this article, two printed planar monopole antennas (PPMA) are presented. In the design of the first PPMA, the structure is divided into sections and they are optimized in the sense of bottom to up strategy. Tapered transitions and inset feed are employed to increase the bandwidth. The antenna operates between 2.37 GHz and 12 GHz with VSWR<2 and an average peak realized gain of 4.95 dB. Therefore, it is suitable for WLAN, WiMAX, UWB, and X-Band applications. The second PPMA is designed by implementing slots on the previous one to include GPS. The resulting antenna operates in the 1.38-1.60 GHz and 2.33-13.74 GHz bands with VSWR<2. As a result, it also includes GPS in addition to the previous bands. The peak realized gain in GPS is 0.47 dB at 1.575 GHz and the average peak realized gain is 4.41 dB for the 2.33-13.74 GHz band. The group delay performances of the proposed PPMAs are also examined and the maximum group delay deviations of the first and the second PPMAs are observed as 1 ns and 1.33 ns, respectively.Article Citation - WoS: 13Citation - Scopus: 18Multi-Band Cpw Fed Mimo Antenna for Bluetooth, Wlan, and Wimax Applications(John Wiley and Sons Inc., 2016) Desde, İrem; Bozdağ, Göksenin; Kuştepeli, AlpIn this letter, multi-band coplanar waveguide (CPW) fed multiple-input-multiple-output (MIMO) antenna is presented for Bluetooth, WLAN and WiMAX applications. The elements of MIMO antenna are identical CPW-fed printed monopole antennas whose bandwidth performances are improved by employing inverse U and meander line slots. In the design of the antennas, a low-cost FR4 substrate is used and the size of the element antennas are optimized as 35 mm x 30 mm. According to the measurements, S11 is below −10 dB in 2.38 GHz – 2.52 GHz and 3.19 GHz – 6.44 GHz bands with 0.2 dB and 2.9 dB average peak realized gains, respectively. The element antennas are placed orthogonally and fed independently to obtain MIMO structure whose size is optimized as 42 mm x 62 mm. The performance of MIMO antenna is also examined in terms of diversity parameters such as envelope correlation coefficient and apparent diversity gain, which are lower than 0.02 and higher than 9.9 in the operating bands, respectively.Article Citation - WoS: 4Citation - Scopus: 8Prioritizing Mcdc Test Cases by Spectral Analysis of Boolean Functions(John Wiley and Sons Inc., 2017) Ayav, TolgaTest case prioritization aims at scheduling test cases in an order that improves some performance goal. One performance goal is a measure of how quickly faults are detected. Such prioritization can be performed by exploiting the Fault Exposing Potential (FEP) parameters associated to the test cases. FEP is usually approximated by mutation analysis under certain fault assumptions. Although this technique is effective, it could be relatively expensive compared to the other prioritization techniques. This study proposes a cost-effective FEP approximation for prioritizing Modified Condition Decision Coverage (MCDC) test cases. A strict negative correlation between the FEP of a MCDC test case and the influence value of the associated input condition allows to order the test cases easily without the need of an extensive mutation analysis. The method is entirely based on mathematics and it provides useful insight into how spectral analysis of Boolean functions can benefit software testing.Article Citation - WoS: 8Citation - Scopus: 10Design of Dual-Mode Dual-Band Photonic Crystal Bandpass Filters for Terahertz Communication Applications(John Wiley and Sons Inc., 2015) Karakılınç, Özgür Önder; Dinleyici, Mehmet SalihIn this study, Photonic Crystal (PhC) dual-mode dual-band bandpass filter is designed and its transmission characteristics are investigated for various configurations. PhC resonator structure is formed by a point defect microcavity that is equipped with one large and three smaller auxiliary perturbation rods. Degenerate modes at each band may also be excited by changing the structure properties of the perturbation. Plane wave expansion method and Finite Difference Time-Domain method are used to analyze the device characteristics. Proposed dual-band dual-mode PhC filter structure can effectively be used for terahertz communication applications.Article Citation - WoS: 12Citation - Scopus: 16The Resonant Behavior of the Fibonacci Fractal Tree Antennas(John Wiley and Sons Inc., 2008) Özbakış, Başak; Kuştepeli, AlpAn investigation of a novel fractal tree antenna with the application to two different geometries is presented. The antenna is designed by using the special Fibonacci number sequence which leads to nonuniform branch length ratios to form the fractal tree. This new approach gives better performance, especially in the miniaturization of the antenna, when compared with the conventional designs. The results obtained from the experiments are also compared with the computed ones and there is a very good agreement between the numerical and measured data.Article Citation - WoS: 2Citation - Scopus: 1Design of Coupling Structures for Groove Guide Resonators(John Wiley and Sons Inc., 2008) Bechteler, Thomas F.; Kuştepeli, Alp; Aydınlık Bechteler, Ayşe SevinçThree different coupling structures for a groove guide resonator operating at 10 GHz are investigated. First, propagatable modes are determined analytically. Then, the efficiency of the coupling structures is investigated by means of the method of moments and measurements. Finally, a groove guide resonator is designed and the resonance spectrum for each coupling structure is computed numerically, applying the finite-difference time-domain method. Numerical results are compared with experimental measurements. There is good agreement between the measured and simulated data.Article Citation - WoS: 3Citation - Scopus: 3Switchless Bidirectional Amplifier for Wireless Communication Systems(John Wiley and Sons Inc., 2007) Aydınlık Bechteler, Ayşe Sevinç; Bechteler, Thomas F.A bidirectional amplifier working at 2.4 GHz is presented in this article. The presented amplifier is able to amplify two signals simultaneously. This, since commonly used radio frequency switches are replaced by circulators. The amplifier is designed on a single small-sized printed circuit board. First, the new amplifier circuit is proposed and characterized. Then, its advantages and design problems are analyzed. Finally, design instructions are setup in order to obtain a good performance of the switchless amplifier within the frequency band of interest.