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Koleksiyondaki öğeler
- MakaleAçık Erişim2024The effects of carbonate and vinegar mixture on selected surface properties of iatandza (Albizia ferruginea) wood; [Iatandza (Albizia ferruginea) odununda seçilmiş bazı yüzey özellikleri üzerine karbonat ve sirke karışımının etkileri]
Ayata, Ümit
The color of wooden materials can be altered through various applications (thermal treatment, bleaching, impregnation, aging, etc.). This study aimed to investigate alterations in color, whiteness index (WI*), and glossiness properties resulting from the application of two distinct solutions (two different types of vinegar and a mixture of carbonate) on the surfaces of iatandza (Albizia ferruginea) wood. A reference group was established, and the surfaces subjected to treatments were compared among themselves. According to the results of the analysis of variance conducted, the solution type prepared over all tests was determined to be statistically significant. The L*, C*, b*, and a* values in the color parameters decreased while the h° value exhibited an increase after the application of solutions. The ∆E* values were measured at 13.63 for the carbonate + vinegar (A) solution and 13.13 for the carbonate + vinegar (B) solution. Furthermore, the calculated differences ∆b*, ∆L*, ∆a*, and ∆C* using color formulas were observed to be negative for both solutions. Glossiness values exhibited reductions in both directions at 60 and 85 degrees, alongside decreases in WI* values in both orientations. It was noted that the application of solutions resulted in alterations to the surface characteristics of the wooden material.
AtıfScopus2OpenAlex4TR Dizin1
İncele - MakaleAçık Erişim2023Performing trajectory tracking control of an unmanned ground vehicle using fractional order terminal sliding mode controller
Sekban, Hayriye Tuǧba; Başçi, Abdullah
In this paper, fractional order terminal sliding mode control (FOTSMC) method is used for trajectory tracking control performance of an unmanned ground vehicle (UGV). Firstly, a kinematic controller is designed to estimate the linear and angular velocities of the vehicle. Then, a FOTSMC design is carried out to track the vehicle reference velocities. Terminal sliding mode control (TSMC) and sliding mode control (SMC) methods are also used to demonstrate the performance of the proposed controller. The simulation results show that the proposed controller improves the tracking error by about 13% over SMC and 6.146% compared to TSMC.
AtıfScopus3WoS3OpenAlex3
İncele - MakaleAçık Erişim2023Scopus SJRQ2Optimizing and investigating durability performance of sandy soils stabilized with alkali activated waste tuff-fly ash mixtures
Yilmaz, Fatih; Kuvat, Ahmet; Kamiloğlu, Hakan Alper
The search for alternative environmentally-friendly materials to Portland cement is increasing its importance in geotechnical engineering as in other fields. In this study, alkali activated waste volcanic tuff (BT) and fly ash (FA) utilized as an alternative to conventional binders. The specific objectives of this paper were to, (1) optimize fly ash, waste tuff and activator content using Response Surface Methodology (RSM), (2) investigate the UCS performance of the optimum amount of alkali-activated fly ash and waste tuff mixtures as a binder in soil stabilization by comparing with various codes, (3) characterize the optimized parameters, (4) examine durability performances of the samples. Optimum binder and activator content and effect of waste tuff on strength characteristics were evaluated statistically with RSM approach. XRF, XRD, FTIR analyses were performed to verify the synthesized alkali activated material in the inner structures of the optimized samples. The durability and mechanical properties of samples stabilized with alkali activated binders against soaking condition, wetting-drying and were investigated. Destructive and non-destructive methods were employed to examine mechanical and durability characteristics. Unconfined compression strength, strength reduction ratio, soil deterioration, and water absorption capacity was taken into account to evaluate durability performances. UCS values of the stabilized samples were compared with limit UCS values suggested by several standards. As a result of the study it was determined that alkali activated waste tuff and fly ash mixture shows significant mechanical and durability performance in soil stabilization, and capable to use as an alternative to conventional non-green binders.
AtıfScopus6WoS4OpenAlex8İncele - MakaleYalnız künye2024Scopus SJRQ1Dynamic Angular Velocity Load-Based Energy Harvesting Analysis for Different Blade Angles and Polarization Directions of Smart Blades
Uyar, M.
Energy consumption and control of electrical devices in flying electric vehicles with propellers such as drones are important for the continuity of the movement process. With this motivation, the piezoelectric energy harvesting performances of the smart drone propeller and smart wind blades are evaluated in order to obtain electrical energy from lead zirconate titanate (PZT) material placed on the propellers. Initially, the effect of smart wind blades with different blade angles on energy harvesting analysis is examined. The energy harvesting performances of the converse (z polarization) and shearing movements (y polarization) of the PZT material placed on the wind blades are compared under different angular rotational velocities. Then, the power outputs obtained depending on the sensor responses of the smart drone propeller with different resistance gains are evaluated according to the polarization directions. The maximum and minimum power output values obtained from the smart drone propeller at 12,000 rpm rotation velocity are measured as about 0.086 and 0.008 W, respectively. The results show that the energy harvesting performance of the z-polarized smart propeller is more effective than the y polarization, and the amount of energy obtained with the increase in the endpoint vibration amplitudes increases as the rotation speed increases.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2023Scopus SJRQ2Cr-substituted nanocrystalline Ni–Co ferrites: tuning dielectric, magnetic, structural, X-band microwave absorption, and characteristic properties
Teber, Ahmet; Sarac, Mehmet F.
The structural, characteristic, dielectric, and magnetic features of Co0.5Ni0.5CrxFe2 − xO4 (0.0 ≤ x≤ 1.0 with a step of 0.2 x-concentration) nanoparticles are prepared via the hydrothermal method. The investigation of characteristics, structural, and magnetic features of the produced nanoparticles are examined through XRD, FT-IR, SEM–EDS, TEM-SAED, and VSM, respectively. AC conductivity and the dielectric investigations are also reported. According to the XRD measurements, all samples have the M-type hexagonal crystal structure nanocrystallites of between 27 and 97 nm. Refined structural parameters using Rietveld analysis are carried out using the TOPAS refinement program. A good match was observed between the diffraction patterns obtained and calculated by Rietveld analysis. Moreover, the morphological analyses indicate that the relatively small spherical structures of Ni–Co ferrites particles can be seen to change from spherical to relatively oval-shaped with increasing chromium content. The results of the FT-IR study show that the spinel structure has formed as predicted because the expected range of absorption bands is present. According to magnetic measurements, Cr-substituted Ni–Co ferrite nanostructures reveal a relatively soft ferromagnetic property. The coercive field (Hc) variation has a propensity to decrease in relation to the Cr-concentration. The electromagnetic constitutive parameters are calculated from measured S-parameters (S11 and S21) using network analyzer and the return losses of the samples are then obtained to determine microwave absorption properties. According to the dielectric and magnetic tangent losses or dissipation factors, both dielectric and magnetic features can mutually reinforce in terms of microwave absorption properties in the X-band. The Cr2O3 impurity peaks obtained by XRD analysis have an effect on the microwave absorption properties. The results of the microwave absorption based on each concentration reveal that there exist electromagnetic wave absorptions between approximately 11 GHz and 12.4 GHz in the X-band. The absorption trend is also towards the Ku-band.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYalnız künye2024Scopus SJRQ2Effect of sesame protein/PVA nanofibers on oil separation and rheological properties in sesame paste
Yuzer, Mustafa Onur; Genccelep, Huseyin
This study aimed to prevent or minimize the oil phase separation that occurs during storage (0-90 days) of sesame paste at room temperature. In order to determine the changes during storage in the sesame paste samples, the zeta potential, rheological properties, and the separated oil ratio were determined. Significant (p < 0.01) effects of applied storage time and additives on the amount of oil separated in sesame pastes were determined. The oil separated in sesame paste samples varied between 3.83% and 16.29%. While the rate of separated oil increased three times in the control group over time, it showed an insignificant (p > 0.05) increase especially in the samples where 2% nanofiber was added. It was determined that the separation of the oil phase from the structure could be prevented up to 24.73% with the addition of SPI and up to 63.02% with addition of SPINL (nanofiber containing protein isolate) compared to the control. Practical applications: During storage, the particles in the sesame paste tend to precipitate, causing oil separation and residue cake, thus negatively affecting the acceptability of consumers. Additives were added in order to prevent or minimize oil phase separation, which occurs in sesame paste stored at room temperature and is not desired by consumers. As additives, nanofibers containing sesame proteins produced by the electrospinning method and sesame protein isolates (SPIs) were added. Added additives acted by preventing the separation of the oil phase from the structure. It has been determined that the addition of SPI to sesame pastes does not completely prevent the problem of oil separation in sesame paste, but is effective in delaying and reducing it. Since the oil decomposition can be reduced, the amount of oil separated and therefore the part that can sink to the bottom will decrease, so sesame paste will be consumed more appropriately and will contribute to the country's economy.
AtıfScopus9WoS7OpenAlex7İncele - MakaleYalnız künye2023Scopus SJRQ2Socioeconomic status and wellbeing as predictors of students' academic achievement: Evidence from a developing country
Erdem, Cahit; Kaya, Metin
The COVID-19 pandemic has deepened the effects of socioeconomic status (SES) and wellbeing (WB) on students' academic achievement, particularly in developing countries; thus, it becomes necessary to understand the nature of these concurrent relationships. This study aimed to explore the relationships between SES, WB and academic achievement, based on the data from the Programme for International Student Assessment (PISA) in 2018 within the Turkish context. In this cross-sectional study, we used hierarchical multiple linear regression analysis to explore how the independent variables predicted academic achievement in blocks based on data from 6890 students attending 186 schools. The study revealed that the model, including the independent variables, predicted students' achievement in reading, mathematics and science; however, the prediction level of demographic factors and domains of WB were very low, while SES had the highest prediction level. The results offer insights into the predictors of academic achievement and educational inequalities in the context of a developing country.
AtıfScopus35WoS28OpenAlex39İncele - MakaleYayıncıda açık erişim2023Scopus SJRQ1Designing New Model-Based Adaptive Sliding Mode Controllers for Trajectory Tracking Control of an Unmanned Ground Vehicle
Sekban, Hayriye Tugba; Basci, Abdullah
This paper proposes three new dynamic model-based adaptive sliding mode controllers (ASMC) for trajectory tracking control of unmanned ground vehicles (UGV). The controllers combine kinematic and dynamic control to achieve asymptotic stability and finite-time convergence and their stability is verified using the Lyapunov stability theory. The controllers are designed to address the challenges posed by uncertainties in vehicle dynamic parameters and outperform the sliding mode control (SMC) method in trajectory tracking control. The simulation results of the proposed controllers are also discussed in terms of performance metrics. The simulation results show that the controller proposed in rule 1 shows the better performance in terms of trajectory tracking, and then the controllers proposed in rules 2 and 3 have good performances, respectively. In addition, when the simulation results are compared, it is seen that the performance of all three proposed controllers is better than the SMC.
AtıfScopus12WoS10OpenAlex13İncele - MakaleYalnız künye2023Scopus SJRQ3An Investigation on the Behavior of 3D Steel Frames Under Progressive Collapse Effect Using Nonlinear Dynamic Analysis
Tayfur, Bilal; Daloǧlu, Ayșe T.
In this study, the nonlinear dynamic analysis of steel structures against progressive collapse was examined, and the adequacy and validity of the analysis duration defined in the regulation were investigated. In addition, the effects of the seismic resistance and design against progressive collapse constraints on the structure were investigated. An optimization algorithm was used in order to conduct the iterative process with appropriate sections. The frames were analyzed to perform one cycle as recommended in the UFC, and then the analysis duration was extended until at least five cycles had been completed. When the UFC was considered only, it was observed that while some of the designs were classified as safe within the duration specified in the UFC, the structural integrity was seen to get into danger in the subsequent cycles. When constraints related to seismic effect are also included in the process, it was seen that the threat disappeared for the frames examined. In addition, it was observed that the steel frame resisted progressive collapse scenarios by creating formations like Vierendeel beams.
AtıfScopus1WoS1OpenAlex2İncele - MakaleYalnız künye2024Synergistic Strategies for Overcoming Salt Stress in Strawberry Farming: The Use of Organic Fertilizers and Plant Growth Promoting Rhizobacteria (PGPR)
Yavuz, Aysegul; Erdogan, Ummugulsum; Turan, Metin; Argın, Sanem; Kocaman, Ayhan
The study was carried out under salt-stress conditions, and three non-microbial commercial organic fertilizers purchased from Humintech GmbH (Grevenbroich, Germany) were applied to the soil for strawberry plants. The three promoters were Fulvagra®, based on fulvic acid, Liqhumus®, based on humic acid, and Microsense Root®, also based on humic acid. Treatment with Fulvagra® resulted in a remarkable 69.90% increase in average fruit weight and a 39.52% increase in yield in strawberry plants. These improvements remained significant when combined with plant growth promoting rhizobacteria (PGPR), resulting in a 61.81% increase in fruit weight and a 45.21% increase in yield. Liqhumus® treatment resulted in a significant 49.95% increase in fruit weight and a 39.30% increase in fruit yield. The introduction of PGPR further enhanced these effects by increasing fruit weight by 87.70% and yield by 63.84%. The Microsense Root® treatment showed 31.07 and 61.87% improvements for the respective parameters. In conjunction with this treatment, the use of PGPR produced the most significant results, with increases of 121.14 and 65.37% for respective parameters. These results indicate that the combined use of non-microbial commercial organic fertilizers with PGPR leads to higher efficiency and is promising for sustainable agricultural practices, particularly in improving the resistance of strawberry plants to salt-induced stress.
AtıfScopus4WoS5OpenAlex5İncele - Derleme MakaleAçık Erişim2022Scopus SJRQ1Impact of different microwave treatments on food texture
Kutlu, Naciye; Pandiselvam, Ravi; Saka, Irem; Kamiloglu, Aybike; Sahni, Prashant; Kothakota, Anjineyulu
Electromagnetic waves are frequently used for food processing with commercial or domestic type microwave ovens at present. Microwaves cause molecular movement by the migration of ionic particles or rotation of dipolar particles. Considering the potential applications of microwave technique in food industry, it is seen that microwaves have many advantages such as saving time, better final product quality (more taste, color, and nutritional value), and rapid heat generation. Although microwave treatment used for food processing with developing technologies have a positive effect in terms of time, energy, or nutrient value, it is also very important to what extent they affect the textural properties of the food that they apply to. For this purpose, in this study, it has been investigated that the effects of commonly used microwave treatments such as drying, heating, baking, cooking, thawing, toasting, blanching, frying, and sterilization on the textural properties of food. In addition, this study has also covered the challenges of microwave treatments and future work. In conclusion, microwave treatments cause energy saving due to a short processing time. Therefore, it can be said that it affects the textural properties positively. However, it is important that the microwave processing conditions used are chosen appropriately for each food material.
AtıfScopus121WoS99OpenAlex125
İncele - MakaleAçık Erişim2023Scopus SJRQ2Characterisation of dextran AP-27 produced by bee pollen isolate Lactobacillus kunkeei AP-27
Yilmaz, Mustafa T.; İspirli, Hümeyra; Alidrisi, Hassan; Taylan, Osman; Dertli, Enes
An exopolysaccharide (EPS) produced by bee pollen isolate Lactobacillus kunkeei AP-27 was characterised in this study. EPS monomeric composition of strain AP-27 was characterised by High-performance liquid chromatography (HPLC) analysis and glucose was the only sugar in the EPS repeating unit. Structural analysis of glucan AP27 by 1H and 13C Nuclear magnetic resonance (NMR) analysis demonstrated that this glucan was a dextran ((1→6)-linked α-D-glucose units as the main body) consisting very low level of (1 → 4)-linked α-D-glucose units (∼ 0.5 %). Dextran AP-27 had a degradation temperature of 308 °C that revealed its superior thermal strength identified by Thermogravimetric (TGA) and Differential scanning calorimetry (DSC) analysis. The molecular weight of dextran AP-27 was determined to be 25 kDa by Gel Permeation Chromatography (GPC) analysis. Crystallographic properties of dextran AP-27 was determined by X-ray diffraction (XRD) analysis that divulged its amorphous feature. Scanning Electron Microscopy (SEM) analysis was applied for microstructural characterisation of dextran AP-27 which revealed its regular sphere like characteristics. These findings suggest that Lactic Acid Bacteria (LAB) strains from different environments such as bee products can be the source for distinct EPS producer strains.
AtıfScopus9WoS8OpenAlex7İncele - MakaleAçık Erişim2022Scopus SJRQ1The impact of ozone treatment on whey concentrate on the flow behaviour, functional and microbiological characteristics of whey powder
Sert, Durmuş; Mercan, Emin
The impact of ozone treatment (OT) for 0 (control) 30, 60, 90 and 120 min to whey concentrate (WC) on powder flow, physicochemical, functional, and microbiological characteristics of whey powders (WPs) was examined. OT decreased the cohesiveness of WC, whereas the firmness, consistency and index of viscosity were not affected. OT caused higher L∗ and b∗ values in WP and improved the solubility and foaming capacity, but decreased foaming stability and bulk density. OT increased the mean particle size of WP samples depending on the treatment time. Higher treatment time of OT resulted in a lower cohesion index. OT decreased caking ability of WP samples and increased flow stability. Compaction coefficient and cohesion index depending on increasing test speed, were generally reduced with higher OT. Overall, powder flow analyses revealed that OT of WC resulted in improved flow behaviour of WP. The microbial load of WP was reduced using OT.
AtıfScopus14WoS10OpenAlex16İncele - MakaleYalnız künye2023Scopus SJRQ3A comparison of the associations between bone turnover markers and different sports fields: combat versus team sports
Yıldız, K.; Uzunçakmak, S. Karabulut; Halıcı, Z.; Özçelik, C.; Yazıcı, A.G.
Sedentary life brings risks that include osteoporosis, while physical activity has many benefits for health in general and the skeletal system. Irisin is a hormone-like myokine regulated by mechanical force and it contributes to cortical and trabecular bone mineral density. This study aimed to investigate the effects of different types of sports on bone health by measuring elite athletes’ fibronectin type III domain 5 (FNDC5), N-terminal collagen type I extension propeptide (PINP), and C-terminal cross-linking telopeptide of type I collagen (CTXI) levels. Combat sports athletes, team sports athletes, and sedentary control subjects were enrolled. Serum levels of proteins were measured by ELISA. FNDC5 levels of elite athletes were higher compared to the sedentary controls (P=0.0014). The highest FNDC5 level was measured in wrestlers among all considered groups. The PINP levels of the athletes were also higher than those of the sedentary control group (P=0.1431). The highest PINP level was determined in boxers. The CTXI levels of the athletes were lower than those of the sedentary control (P<0.0001). The lowest CTXI level was seen in boxers. The FNDC5 and PINP levels of combat sports athletes were higher than those of team sports athletes (P=0.0134 and P=0.0262, respectively), while the CTXI levels of combat sports athletes were lower than those of team sports athletes (P<0.0001). Our results indicated that FNDC5, PINP, and CTXI levels are associated with physical activity. The effect of the exercises performed by athletes of specific sports on bone health has not been studied in much detail before. Combining different exercises for athletes of a particular sport may be more beneficial for bone health.
- MakaleYalnız künye2023Scopus SJRQ2Yttrium-substituted Co0.5Ni0.5YxFe2-xO4 ferrites as microwave absorbers by investigating structural, magnetic, dielectric, and absorption characteristics
Teber, Ahmet; Sarac, Mehmet F.
The effect of Yttrium Substitution on Co0.5Ni0.5YxFe2- xO4 (0.0 ≤ x ≤ 1.0) Ferrites as Microwave Absorbers was investigated to include structural, magnetic, dielectric and X-band absorption properties. The main objective of this work is to enhance microwave absorption properties of materials with interesting dielectric/magnetic behaviors by doping rare earth element of Yttrium based on transition metals. The hydrothermal method was used to create Yttrium (Y) substituted nanoparticles, and the effects of Y-ion substitution on the characteristics, structural, magnetic features were examined by XRD, FT-IR, SEM-EDS, TEM-SAED, and VSM, respectively. Electromagnetic properties were obtained from microwave scattering parameters measured via a metal-backed transmission line and Nicholson-Ross Weir techniques using a vector network analyzer (VNA) in conjunction with an X-band waveguide set. Return loss (RL) values of the samples were obtained from the electromagnetic constitutive parameters (permittivity and permeability). According to the XRD measurements, hexagonal crystal structure of ferrite and YFeO3 as secondary phase nanocrystal sizes are between 11 and 67 nm. Refined structural parameters using Rietveld analysis are carried out using the TOPAS refinement program. A good match was observed between the diffraction patterns obtained and calculated by Rietveld analysis. Moreover, the morphological analyses indicate that the relatively small spherical structures of Ni-Co ferrites particles can be seen to change from spherical to hexagonal-shaped with increasing yttrium concentration. The results of the FT-IR study show that the spinel structure has formed as predicted because the expected range of absorption bands is present. According to magnetic measurements, the coercivity (Hc) results show a modest increase in porosity as the Y-content rises. The results revealed that the minimum RL value and bandwidth vary significantly with the amount of Yttrium in the mixture, indicating that the obtained structures will be useful for broadband microwave applications.
AtıfScopus10WoS11OpenAlex12İncele - Kitap BölümüYalnız künye2024Afghans ante portas: Looking at immigrants in Turkiye through google's peephole
Keskin, Savaş; Kömür, Gökhan
Bauman"s approach, conceptualised as "strangers at out door/ante portas", requires a relationship that requires us to look at immigrants from inside the door. This study focuses on how Afghans, who are collectively expected to be hated as the new "dangerous" strangers, appear in Turkiye. The images pro-vided by Google searches become a suffcient "peephole" through which to collectively see and imagine Afghans. This is because the "peephole" metaphor encompasses a symbolic context in which the fear of the "strangers at out door (ante portas)", the desire to see/observe them, and the parallax effect can be symbolically represented at a common root. In the study, by typing "Afghans" and "Afghan Migrants" in Turkish into the Google search bar, the visual (photographic) search results are used to establish relationships with alienation and otherness in the visual representation of Afghan identity.
- MakaleYalnız künye2021SOME NEW INEQUALITIES FOR (α, m1, m2)-GG CONVEX FUNCTIONS VIA GAMMA AND INCOMPLETE GAMMA FUNCTIONS
Kadakal, Mahir
In this study, we introduced the concept of (α, m1, m2)-GG convex functions; then we obtained Hermite-Hadamard type inequalities for these type of function classes via gamma and incomplete gamma functions together with Hölder, power-mean, Hölder-İşcan and improved power-mean integral inequalities.
- MakaleYalnız künye2024Scopus SJRQ1The effect of sociodemographic characteristics and polypharmacy on loneliness and social isolation in community-dwelling older adults
Sönmez Sari, Ebru; Çetinkaya Özdemir, Serap; Semerci Çakmak, Vahide; Kurt, Fatma
The aim of this study was to assess the impact of sociodemographic factors and polypharmacy on loneliness and social isolation in older adults. This cross-sectional study included 370 older adults with and without polypharmacy. The data were gathered via the Personal Information Form, Loneliness Scale for Elderly, and Lubben Social Network Scale-Revised. A multivariate ANOVA (MANOVA) was conducted to assess the impact of independent variables on the combined dependent variables. Loneliness and social isolation were found higher in older adults with polypharmacy. In addition, loneliness and social isolation are more common in women, individuals with low educational attainment, single individuals, individuals with low income, individuals living in rural areas, individuals with poor family relationships, individuals not living with their families and individuals with chronic diseases. It is thought that the findings of this study will be guiding for all health professionals working in the field of elderly health in interventions to be planned for the elderly population.
AtıfScopus6WoS5OpenAlex5İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ1Enhanced thermal and angular velocity-induced hybrid piezoelectric energy harvesting of smart turbine blades
Uyar, Mehmet
In this study, an approach is proposed to examine hybrid piezoelectric energy harvesting performances from vibrations induced by thermal and angular velocity loads in order to generate energy from the smart turbine blade. In the proposed method, a smart turbine blade is formed by patching the piezoelectric material to the root surface of the turbine blade. A finite element (FE) model of the smart turbine blade is established and then it is validated with a smart blade model in a reference study to test the reliability and accuracy of the FE method. The defined loads are applied to the smart blade to obtain energy from mechanical vibrations induced by thermal and angular velocity loads. Temperature distribution, voltage, and vibration results obtained from energy harvesting analysis under different thermal and angular velocity loads are presented. In order to investigate the energy conversion efficiency of the energy obtained from the system, the energy harvesting circuit is tested in terms of battery discharge times and power output values. The results show that while the maximum energy conversion in the thermally induced smart turbine blade is 11.9 W, a power output of 12.3 W is obtained from the hybrid energy harvesting mechanism under angular velocity and heat flux loads.
AtıfScopus5WoS5OpenAlex3İncele - MakaleAçık Erişim2024Ultra-thin Polarization Converter Using Single Layer Metasurface for X-, Ku-, and K-Band Applications
Arslan Madak, Seher Şeyma; Teber, Ahmet; Topkaya, Ramazan
In this article, an ultrathin (λ0/14.9), single layer, reflective type polarization converter for either linear-to-circular (LP-to-CP) or linear-to-linear (LP-to-LP) polarization conversion is reported. It has been demonstrated to achieve the LP-to-CP conversion at two separate frequency bands, including 11.52-11.84GHz and 19.83-20.01GHz. The circular polarization type is specified as a right-hand circular polarization (RHCP) for the first band and a left-hand circular polarization (LHCP) for the second band. In both of frequency bands, the metasurface structure reveals highly efficient features. Besides that, the metasurface structure exhibits highly efficient features within 3-dB bandwidths of 10.29-12.58GHz and 19.32-20.50GHz. Crucial parameters of polarization conversion such as ellipticity, axial ratio, and |Eco|/|Ecross| are confirmed to be in good agreement with another one. The metasurface structure's angular stability up to 200 oblique incidence angles makes it useful for beam scanning antennas. CST Microwave Studio program is utilized to carry out extensive simulations. This presented study offers a low cost, relatively high-performance, ultrathin polarization converter capable of linear-to-linear and circular polarization conversion in the X-, Ku-, and K-bands.
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