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Öğe The analysis of PV power potential and system installation in Manavgat, Turkey-A case study in winter season(Pergamon-Elsevier Science Ltd, 2014) Kesler, Selami; Kivrak, Sinan; Dincer, Furkan; Rustemli, Sabir; Karaaslan, Muharrem; Unal, Emin; Erdiven, UtkuThis study presents an analysis of solar energy potential and data with seasonal variation in region of Manavgat in Antalya, which has one of the highest solar energy potential in Europe. Expectation in the region is simulated for every month and measurements taken from PV power system installed there are compared with simulated results in winter season. Also, some actual harvested data from thin films and monociystalline types are presented as a case study to evaluate the solar energy potential of the region, comparatively. Besides, importance of the sun tracking system is emphasized by simulation studies via PV Geographical Information System (PVGIS) from point of increasing the yields in selected region. Estimated results from two-axis tracking system are evaluated and compared with output of the fixed-angle PV systems installed there for both thin film and monocrystalline type PV panels. Also, temperature effects on performance of the PV systems are reviewed briefly because of daily high temperature of the region. In particular, it is observed that harvested solar energy from thin film type panels is close to the monocrystalline types, depending on the less effects of high ambient temperature on thin film PV panel's efficiency with respect to the monociystalline type. Specifically, despite the high solar energy potential, this PV power system installation is the first project in the region. Thanks to this project it is evaluated that thin-film PV panels can be used in the region more favorable, which can be obtained cheaper than the others. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.Öğe The analysis on sun tracking and cooling systems for photovoltaic panels(Pergamon-Elsevier Science Ltd, 2013) Rustemli, Sabir; Dincer, Furkan; Unal, Emin; Karaaslan, Muharrem; Sabah, CumaliThis paper presents a review study on the effects of sun tracking and cooling systems. So far, many studies (and case studies too) have been analyzed and evaluated in the literature. Existing studies show that sun tracking system is significantly affecting energy generation capacity of photovoltaic panel. Other effecting parameter is the cooling system which has small effect on PV panel power generation but this totally depends on the location of installation system. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.Öğe Asymmetric transmission of linearly polarized electromagnetic waves using chiral metamaterials with constant chirality over a certain frequency band(World Scientific Publ Co Pte Ltd, 2014) Dincer, Furkan; Karaaslan, Muharrem; Akgol, Oguzhan; Unal, Emin; Sabah, CumaliIn this study, a dynamic chiral metamaterial (MTM) structure leading to an asymmetric electromagnetic (EM) wave transmission for linear polarization is presented. The structure is composed of square-shaped resonator with gaps on both sides of a dielectric substrate with a certain degree of rotation. The dynamic structure is adjustable via various parameters to fit any desired frequency ranges. Theoretical and experimental analysis of the proposed structure are conducted and given in detail. The suggested model can provide constant chirality over a certain frequency band and thus, it can be used to design myriad novel devices such as EM transmission and antireflection filters, and polarization rotators for desired frequencyÖğe ASYMMETRIC TRANSMISSION OF LINEARLY POLARIZED WAVES AND DYNAMICALLY WAVE ROTATION USING CHIRAL METAMATERIAL(Emw Publishing, 2013) Dincer, Furkan; Sabah, Cumali; Karaaslan, Muharrem; Unal, Emin; Bakir, Mehmet; Erdiven, UtkuThe asymmetric transmission of the linearly polarized waves at normal incidence through the lossy anisotropic chiral structure is demonstrated. The proposed chiral metamaterial structure is composed of hi-layered discontinuous cross-wire-strips, and it is utilized in order to realize polarization rotation. Firstly, the theoretical relations between the incident polarization and the polarization rotation are derived using transmission matrices. Secondly, a strong and dynamically asymmetric transmission of linearly polarized electromagnetic wave through the chiral metamaterial has been demonstrated for microwave region, both by simulation and experimentally. The experiment results are in good agreement with the simulation ones. It can be seen from the results that the proposed chiral metamaterial structure can be used to design novel polarization control devices for several frequency regions.Öğe Biosensor applications of chiral metamaterials for marrowbone temperature sensing(Taylor & Francis Ltd, 2015) Sabah, Cumali; Dincer, Furkan; Karaaslan, Muharrem; Bakir, Mehmet; Unal, Emin; Akgol, OguzhanIn this paper, we have designed, simulated, and analyzed a microwave biosensor based on chiral metamaterials (MTMs) to detect pig biological tissues which are widely used as a trial for medical explorations and researches. There are various types of biosensor structures based on MTMs in the literature. However, only a limited number of study is conducted on biosensors based on chiral MTMs; therefore, our study is one of the pioneer works for this type of research. The proposed diamond-shaped resonator-based structures are numerically investigated and analyzed in detail in the microwave frequency regime. The results are in good agreement which lead us to conclude that our structure can be easily used as an effective instrument for biosensing applications in medical technologies.Öğe Chiral metamaterial structures with strong optical activity and their applications(Spie-Soc Photo-Optical Instrumentation Engineers, 2014) Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Akgol, Oguzhan; Sabah, CumaliWe numerically and experimentally introduce a chiral metamaterial (MTM) showing strong optical activity, dynamical circular dichroism, and mechanical tunability because of its efficient design. The proposed chiral MTM structure is composed of bi-layered discontinuous cross-wire-strips, and utilized in order to realize polarization rotation. It provides a giant negative refractive index and a large chirality. We also present a detailed numerical analysis in order to explain the physical interpretation of the designed structure mechanism with a parametric study. Moreover, an MTM absorber application of the proposed chiral MTM is presented to show an additional feature of the model. The introduced chiral design offers a much simpler geometry and more efficient results. In addition, the structure provides chiral nihility unlike the other chiral MTM studies in the literature. The experimental results of the fabricated prototype are in good agreement with the numerical simulations. As a result, the suggested chiral MTM enables myriad potential applications in polarization converters, radar, and military technologies. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)Öğe Chiral Metamaterials with Strong and Dynamically Optical Activity(Ieee, 2013) Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Bakir, Mehmet; Sabah, Cumali; Delihacioglu, KemalIn this study, chiral metamaterial that creates strong optical activity and dynamical circular dichroism due to geometry of the structure (gammadion-bilayer cross-wires) is presented. It includes the gammadion with discontinuous bilayer cross wire patterned on opposite sides. The designed chiral metamaterial offers easier fabrication and more efficient result. Also, transmission and reflection coefficients, theta and chirality coefficient of the medium are independently analyzed. It provides strong and dynamical optical activity due to the high chirality. The experimental results match with the results of the numerical study.Öğe Design of Polarization and Incident Angle Insensitive Dual-Band Metamaterial Absorber Based on Isotropic Resonator(Emw Publishing, 2014) Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Delihacioglu, Kemal; Sabah, CumaliPolarization and incident angle independent metamaterial-based absorber (MA) which acts as a strong dual-band resonator is designed and constructed. Besides, a method to design single/dualband MA is presented in detail. The proposed model is based on isotropic ring resonator with gaps and octa-star strip (OSS) which allows maximization in the absorption because of the characteristic features of the structure. Reflection and absorption responses are obtained both numerically and experimentally and compared to each other. Two maxima in the absorption are experimentally obtained around 90% at 4.42 GHz for the first band and 99.7% at 5.62 GHz for the second band which are in good agreement with the numerical simulations (95.6% and 99.9%, respectively). The numerical studies verify that the dual-band MA can provide perfect absorption at wide angles of incidence for both transverse electric (T E) and transverse magnetic (TM) waves. The proposed model can easily be used in many potential application areas such as security systems, sensors, medical imaging technology.Öğe Design of Polarization- and Incident Angle-Independent Perfect Metamaterial Absorber with Interference Theory(Springer, 2014) Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Akgol, Oguzhan; Sabah, CumaliA perfect metamaterial absorber is realized and its properties are theoretically, numerically and experimentally investigated at microwave frequencies. In addition, polarization and incident angle independencies are also tested for the structure. Theoretical, numerical and experimental results show that the proposed model has many advantages compared to those in the literature, such as perfect absorption, polarization and incident angle independencies, very simple design, and operation over a sufficiently wide band. A simple configuration is chosen for the proposed model so that it can be easily tuned for other frequency regimes to realize new absorbers for applications such as sensors and stealth technology.Öğe Design of tunable and dual/multi-band metamaterial based perfect microwave absorber(Ios Press, 2015) Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Sabah, CumaliTunable and multi-band metamaterial (MTM) based perfect microwave absorber (MA) is designed, implemented, and characterized. Firstly, dual-band MA with has two distinct resonances is investigated both numerically and experimentally which is also tested according the incident angle and polarization independencies. Then, the modified versions of MA are investigated and compared with respect to their absorbance, mechanical tunability, and multi-band characters. As a result, the suggested MAs with perfect absorption (including incident angle and polarization independencies) display good performance among their counterparts and can be used in myriad potential applications such as high frequency and sensor applications which are also presented.Öğe DUAL-BAND POLARIZATION INDEPENDENT METAMATERIAL ABSORBER BASED ON OMEGA RESOANATOR AND OCTA-STARSTRIP CONFIGURATION(Emw Publishing, 2013) Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Sabah, CumaliDual-band metamaterial absorber (MA) with polarization independency based on omega (Omega) resonator with gap and octastar strip (OSS) configuration is presented both numerically and experimentally. The suggested MA has a simple configuration which introduces flexibility to adjust its metamaterial (MTM) properties and easily re-scale the structure for other frequencies. In addition, the dualband character of the absorber provides additional degree of freedom to control the absorption band(s). Two maxima in the absorption are experimentally obtained around 99% at 4.0 GHz for the first band and 79% at 5.6 GHz for the second band which are in good agreement with the numerical simulations (99% and 84%, respectively). Besides, numerical simulations validate that the MA could achieve very high absorption at wide angles of incidence for both transverse electric (TE) and transverse magnetic (TM) waves. The proposed MA and its variations enable myriad potential applications in medical technologies, sensors, modulators, wireless communication, and so on.Öğe Electromagnetic Energy Harvesting By Using Tunable Metamaterial Absorbers(Ieee, 2015) Bakir, Mehmet; Karaaslan, Muharrem; Dincer, Furkan; Akgol, Oguzhan; Unal, Emin; Delihacioglu, Kemal; Sabah, CumaliIn this study, electromagnetic (EM) energy harvesting by using metamaterial absorber is numerically explained. Operation frequency is 2.40 GHz since it is the industrical scientific and medical (ISM) band. This band is especially chosen due to most of the customer electronic devices are working in this band. Split ring resonator that have two splits on it used in this study, chip resistors are placed on these splits for wireless energy transfer to the devices. 83.6% efficient electromagnetic energy harvesting is theoretically realized.Öğe Flexible chiral metamaterials with dynamically optical activity and high negative refractive index(World Scientific Publ Co Pte Ltd, 2015) Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Akgol, Oguzhan; Sabah, CumaliWe demonstrate numerically and experimentally chiral metamaterials (MTMs) based on gammadion-bilayer cross-wires that uniaxially create giant optical activity and tunable circular dichroism as a result of the dynamic design. In addition, the suggested structure gives high negative refractive index due to the large chirality in order to obtain an efficient polarization converter. We also present a numerical analysis in order to show the additional features of the proposed chiral MTM in detail. Therefore, a MTM sensor application of the proposed chiral MTM is introduced and discussed. The presented chiral designs offer a much simpler geometry and more efficient outlines. The experimental results are in a good agreement with the numerical simulation. It can be seen from the results that, the suggested chiral MTM can be used as a polarization converter, sensor, etc. for several frequency regimes.Öğe Giant Circular Dichroism in Chiral Metamaterials(Ieee, 2013) Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Bakir, Mehmet; Erdiven, Utku; Sabah, CumaliWe demonstrate numerically and experimentally that uniaxial chiral metamaterial creates giant optical activity and circular dichroism due to the large chirality. Also, transmission and reflection coefficients, circular dichroism and chirality values are separately examined and evaluated. The presented chiral designs are combined of the discontinuous bilayer cross-wire patterned on opposite sides. It offers a much simpler geometry and more efficient results. The experimental results are in good agreement with the numerical simulations.Öğe Increasing Bandwidth in Antenna Applications By Using Chiral Metamaterials(Ieee, 2015) Dincer, Furkan; Karaaslan, Muharrem; Bakir, Mehmet; Akgol, Oguzhan; Unal, Emin; Delihacioglu, Kemal; Sabah, CumaliChiral metamaterials are such materials that cannot be found in the nature and show exotic properties as negative refraction index. One of the most important properties of chiral metamaterials is to show optical activity by changing the polarization of the electromagnetic wave. In this way, an electromagnetic wave can be directed and can be controlled. Furthermore, cross coupling is created between electric field and magnetic field in the chiral medium In this study, focusing gain and effects on the antenna applications are searched. Since chiral metamaterials have exotic properties, they have advantages in antennas, gain, bandwidth and designing small material dimensions. 1 GHz bandwidth is obtained in this study.Öğe Low profile antenna radiation enhancement with novel electromagnetic band gap structures(Inst Engineering Technology-Iet, 2013) Karaaslan, Muharrem; Unal, Emin; Tetik, Erkan; Delihacioglu, Kemal; Karadag, Faruk; Dincer, FurkanThe authors design, characterise and fabricate electromagnetic band gap (EBG) structure composed of three different scale planar rectangular mushrooms for low profile antenna applications. Proof of principle demonstration of surface wave minimisation is realised between three different bands depending on mushroom numbers in one unit cell and low profile antenna radiation pattern enhancement is observed by monitoring transmission changes of surface waves using both two different numerical methods and measurements. Three different scale rectangular mushrooms show significantly better performance and wider EBG than many other EBG systems for improved antenna applications such as bow-tie and logarithmically periodic antennas.Öğe New generation planar chiral metamaterials with small and constant chirality over a certain frequency band(World Scientific Publ Co Pte Ltd, 2015) Dincer, Furkan; Karaaslan, Muharrrem; Akgol, Oguzhan; Unal, Emin; Demirel, Ekrem; Sabah, CumaliChiral metamaterial (MTM) researchers generally concentrate and aim to obtain large chirality with optical activity in certain frequencies. However, new generation planar chiral MTM which have small and constant/flat chirality over a certain frequency band have not queried by this time in literature. In fact, this area is mostly ignored by researchers. This study, first one according to best of our knowledge in the literature, is investigating the small and constant/fixed chirality and focuses on the new generation planar chiral MTM based on circular split ring resonators (SRRs), in details. It can be seen from the results that the proposed model can provide small and constant/flat chirality over a certain frequency band and thus it can be used to design myriad novel devices such as polarization rotators, and electromagnetic transmission and antireflection filters for several frequency regions.Öğe Perfect metamaterial absorber with polarization and incident angle independencies based on ring and cross-wire resonators for shielding and a sensor application(Elsevier Science Bv, 2014) Sabah, Cumali; Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Akgol, Oguzhan; Demirel, EkremWe report the design, characterization and experimental verification of a perfect metamaterial absorber (MA) based on rings and cross wires (RCWs) configurations that operate in the microwave regime. The suggested [VIA provides perfect absorption with incident angle and polarization independencies which can be used for various shielding applications. Maximum absorption rate is 99.9% at 2.76 GHz for simulation and 99.4% at 2.82 GHz for experiment, respectively. The experimental results of the fabricated prototype are in good agreement with the numerical simulations. We also present a numerical analysis in order to explain physical interpretation of MA mechanism in detail. Moreover, a sensor application of the proposed MA is introduced to show additional feature of the model. As a result, proposed MA enables myriad potential applications in S band radar and medical technologies. (c) 2014 Elsevier By. All rights reserved,Öğe Photonic crystal bend and applications(Elsevier Gmbh, 2013) Erdiven, Utku; Karadag, Faruk; Karaaslan, Muharrem; Unal, EminIn this study, 2D square lattice photonic crystal bend structure based on high index rods placed in air is designed by removing two cross lines of rods to realize two optical channels. The alteration of transmitted energy in the channels depending on rods radius changes is observed in the simulations. Time domain simulation results obtained by FDTD analyses exhibit that, when transverse magnetic (TM) Gaussian point source is applied from left channel, up to 92% of the incident energy can be channelized into a vertical channel. Variation of rods radius in the corner of bend affects considerable to the magnitude of reflected wave in the source channel and the time delay between the incident and reflected waves. Sensitivity analysis of W1 waveguide bend in a photonic crystal (PhC) is achieved to optimize PhC bend structure frequency response. Results of these numerical optimizations can be used to design novel compact switches and optical sensors. (C) 2012 Elsevier GmbH. All rights reserved.Öğe Polarization and angle independent perfect metamaterial absorber based on discontinuous cross-wire-strips(Taylor & Francis Ltd, 2014) Dincer, Furkan; Karaaslan, Muharrem; Unal, Emin; Akgol, Oguzhan; Demirel, Ekrem; Sabah, CumaliThis study presents design, fabrication, and measurement of a metamaterial absorber (MA) based on discontinuous cross-wire-strip (CWS) resonators. This suggested that MA has a simple geometry configuration and introduces perfect absorption approximately 99.79% at 3.42 GHz for simulation and 99.72% at 3.44 GHz for experiment. In addition, the designed model can be used to realize the broadband absorber for desired frequency ranges. Besides, numerical simulations validate that the MA could achieve very high absorptions at wide angles of incidence for both transverse electric and transverse magnetic waves. The experimental results are in good agreement with the numerical simulations. Moreover, this study presents a numerical analysis in order to explain physical interpretation of MA mechanisms in detail. The proposed model and its variations enable myriad potential applications such as stealth and radar technologies.
