Yazar "Aydin, Emine Avsar" seçeneğine göre listele

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    3D printed honeycomb transition metal decorated electrodes for hydrogen production
    (Elsevier Sci Ltd, 2024) Mert, Mehmet Erman; Nazligul, Huseyin; Aydin, Emine Avsar; Mert, Basak Dogru
    In this study, a PV-wind hybrid system was proposed as a power source for hydrogen production by alkaline electrolysis and it was examined MATLAB simulation for Adana region. In the alkaline electrolysis cell, lab-made 3D printed cathode substrates were used and its electrocatalytic activity was enhanced via electrodeposition of Ni, Cu and NiCu. The characterization was achieved via scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, contact angle measurement and X-Ray diffraction analysis. The electrochemical performance was determined via linear sweep voltammetry, cyclic voltammetry, Tafel polarization measurements, electrochemical impedance spectroscopy, chronoamperometry. Results showed that 3DNiCu electrode exhibited nodular shaped homogeneous surface characteristics and NiCu (111) and (200) crystalline morphology; it also demonstrated lower polarization resistance and higher current density during alkaline electrolysis procedure.
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    3D-Printed Antenna Design Using Graphene Filament and Copper Tape for High-Tech Air Components
    (Sae Int, 2023) Aydin, Emine Avsar; Bicer, Mustafa Berkan; Mert, Mehmet Erman; Ozgur, Ceyla; Mert, Basak Dogru
    Additive manufacturing (AM) technologies can produce lighter parts; reduce manual assembly processes; reduce the number of production steps; shorten the production cycle; significantly reduce material consumption; enable the production of prostheses, implants, and artificial organs; and produce end-user products since it is used in many sectors for many reasons; it has also started to be used widely, especially in the field of aerospace. In this study, polylactic acid (PLA) was preferred for the antenna substrate because it is environmentally friendly, easy to recycle, provides convenience in production design with a three-dimensional (3D) printer, and is less expensive compared to other available materials. Copper (Cu) tape and graphene filament were employed for the antenna patch component due to their benefits. The comprehensive comparative analysis between a full-wave model and a 3D-printed prototype of the antenna via the CST Microwave Studio program was demonstrated here. The surface characterization was achieved with scanning electron microscope and energy dispersive X-ray (SEM-EDX) and X-ray diffractometer (XRD) analysis. The homogeneous Cu and oxidized graphene (GO) were detected. The weight percent of carbon (C) and oxygen (O) on the graphene surface was 59.82% and 40.18%, respectively. The Cu (111), Cu (200), and Cu (220) peaks were determined on the Cu tape. The GO (011) peak was seen in the XRD spectra of the graphene sheet. The simulation and measurement comparisons are quite satisfactory. The antennas, produced using a conventional 3D printer, will be beneficial for various applications in aeronautics and astronautics.
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    A novel 3D printed curved monopole microstrip antenna design for biomedical applications
    (Springer, 2021) Bicer, Mustafa Berkan; Aydin, Emine Avsar
    This paper proposes a novel and compact monopole microstrip antenna design with a three-dimensional (3D) printed curved substrate for biomedical applications. A curved substrate was formed by inserting a semi-cylinder structure in the middle of the planar substrate consisting of polylactic acid. The antenna was fed with a microstrip line, and a partial ground plane was formed at the bottom side of the substrate. The copper plane with two triangular slots is arranged on the curved semi-cylinder structure of the substrate. The physical dimensions of the radiating plane and ground plane were optimally determined with the use of the sparrow search algorithm to provide a wide-10 dB bandwidth between 3 and 12 GHz. A total of six microstrip antennas having different parameters related to physical dimensions were designed and simulated to compare the performance of the proposed antenna with the help of full-wave electromagnetic simulation software called CST Microwave Studio. The proposed curved antenna was fabricated, and a PNA network analyzer was used to measure the S-11 of the proposed antenna. It was demonstrated that the measured S-11 covers the desired frequency range.
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    A Novel Triple-Band Microstrip Patch Antenna for Breast Cancer Detection Systems Fabricated with Recyclable Filaments
    (Springer, 2024) Aydin, Emine Avsar
    Breast cancer ranks as the second most common cause of mortality among women globally, with the potential to increase survival rates by 97% through early detection. This study focuses on developing an innovative triple-band microstrip patch antenna designed to operate within the 2-6 GHz frequency spectrum. Simulation tests were conducted to evaluate its efficacy in early breast cancer detection. The antenna, constructed from copper tape and five different substrates (Felt, FR4, PET, PLA, TPU), was chosen considering its advantages for various applications. This design prioritizes wearer comfort while ensuring functionality and allows for producing antenna structures in desired geometries using 3D printing, even in complex configurations. With a general size of 30 x 30 mm2, the antenna underwent analyses on tumor-free models with tumors of different shapes and sizes, and additionally, to evaluate the performance of multiple antennas in detecting cancers, tumor models with 2 and 3 antenna numbers were analyzed in a total of six different breast scenarios. Critical performance parameters such as specific absorption rate (SAR), return loss (S11), and voltage standing wave ratio (VSWR) were obtained for each generated model. Simulation outcomes indicated SAR values within the permissible threshold for medical applications. Moreover, VSWR values maintained acceptability, while variations in return losses were contingent upon tumor dimensions, location, and the number of antennas used. Furthermore, the antenna's adaptability to bending was scrutinized through bending analyses, affirming its robustness, and sustained operational capability. One of the significant contributions of the study is the utilization of recyclable filaments such as PLA, TPU, and Protopasta in experimental investigations, providing a pathway for producing environmentally friendly and flexible antennas and breast phantoms. This study offers a way to develop more sensitive and reliable breast cancer screening and early diagnosis tools.
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    AN APPROXIMATE SOLUTION FOR THE PLANE WAVE DIFFRACTION BY AN IMPEDANCE STRIP: H-POLARIZATION CASE
    (Univ North, 2016) Aydin, Emine Avsar; Ikiz, Turgut
    In this study, the diffraction of H-polarized plane wave by an infinitely long strip which has the same impedance on both faces with a width of 2a is investigated by using an analytical-numerical method. The diffracted field is obtained by an integral equation in terms of the electric and magnetic currents induced by the incident field. This integral equation is reduced to two uncoupled integral equations that include only induced electric and magnetic currents separately. Both of the currents are defined as a sum of infinite series of Gegenbauer polynomials with unknown coefficients satisfying the edge conditions. The integral equations are transformed to linear algebraic equations by using analytical methods and the unknown coefficients are determined by solving numerically obtained matrix equations. Numerical examples on the RCS (radar cross section) are presented, and the far field scattering characteristics of the strip are discussed in detail. Some of the obtained results are compared with the other existing method.
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    Analyzing equilateral triangle compact microstrip antennas using Gaussian process regression for telemedicine and mobile biomedical imaging systems
    (Springer, 2023) Bicer, Mustafa Berkan; Aydin, Emine Avsar
    Antennas are vital in the internet of things (IoT) for enabling telemedicine and healthcare communication between devices and networks. They receive and transmit signals, extending range, improving efficiency, and reducing power consumption. Antennas are versatile and can be integrated into devices or added as external modules. Their flexibility and adaptability are important in applications involving humans, as they can bend and conform to the shape of the body. Overall, antennas are a crucial and adaptable component of IoT technology. The first thing that needs to be done is to determine the frequency at which the antenna should operate for the problem at hand and design an antenna that can work at those resonant frequencies. In this study, equilateral triangular-shaped compact microstrip antennas (ETMAs) were chosen, and their resonance frequencies were calculated using the Gaussian process regression method (GPR). For this purpose, 630 ETMA were simulated, and a dataset was created utilizing the antenna characteristics and resonant frequencies. Support vector machines (SVM), artificial neural networks (ANN), and GPR models were trained on the obtained data set. To validate the performance of the trained models, two ETMAs with an outer length of 50 mm and an inner slot length of 5 mm were fabricated utilizing polylactic acid (PLA) and felt-based substrates with copper tape as the conducting material. The accuracy of the resonant frequency estimation using the GPR approach for the fabricated antennas is 2.833% and 1.706% for the PLA- and felt-based antennas, respectively, when compared to the measurement results. The GPR model trained in this study has an accuracy of 0.470% and 0.662% when compared to simulations in the literature and measurement results, respectively. In addition, one of the designed antennas is in wearable form, and the other is PLA, produced with a low-cost 3D printer, allowing continuous monitoring of patients with high cancer risk. In this article, an easier and cheaper microstrip patch antenna that can be used for imaging and telemedicine applications is designed with a copper band on one flexible and one rigid substrate, and its performance is analyzed experimentally.
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    Breast cancer detection using K-nearest neighbors data mining method obtained from the bow-tie antenna dataset
    (Wiley, 2017) Aydin, Emine Avsar; Keles, Mumine Kaya
    Breast cancer, has been a significant cancer type for women on the society. Early diagnosis and timely medical treatment are important key factors spreading to the other tissues and permitting long-time survival of patients. Since the existing methods have several serious shortfalls, microwave imaging method for the diagnosis of early stage tumors has been interested by different scientific research groups in terms of moderating endogenous the electrical property difference between healthy tissue and malignancies. In this article, both an ultra-wideband bow-tie antenna with enhanced bandwidth and a 3D breast model which has different electrical properties which are permittivity and conductivity is created in simulation tool to solve electromagnetic field values. Return loss, VSWR, and radiation pattern characteristics, which are significant antenna parameters, are simulated and obtained whether the antenna possess an efficient characteristic or not. Electric field values over the breast tissue in which there is a tumor or not tumor are evaluated. In this article, above-mentioned values of frequency bandwidth, dielectric constant of antenna's substrate, electric field, and tumor information were consisted in their dataset. This dataset obtained from the Bow-Tie Antenna was used to detect the breast cancer with one of the data mining method, which is K-Nearest Neighbor Algorithm.
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    Design and Fabrication of Rectangular Microstrip Antenna with Various Flexible Substrates
    (Institute of Electrical and Electronics Engineers Inc., 2021) Bicer, Mustafa Berkan; Aydin, Emine Avsar
    In addition to being small, light, practical, and cheap to manufacture, microstrip antennas are also exceedingly difficult to obtain the most suitable electrical parameters such as resonance frequency, bandwidth, return loss, gain, efficiency, and standing wave ratio. To achieve this, researchers are trying different physical structures and applying optimization techniques to them in order to obtain the most suitable radiation power and shape in different sizes and materials. Especially at high frequencies, the dielectric property of the material used can change all the parameters of microstrip antennas and affect the antenna performance to a great extent. The purpose of this study is to investigate the impacts of the physical structure and electrical properties of various textile materials and obtaining the most suitable material. For this purpose, textile-based wearable rectangular microstrip antenna designs were carried out on three different resonant frequency bands, which are widely used with different textile products such as felt, photo paper, and fiberglass, and their performances were examined. The proposed antennas on felt, photographic paper, and fiberglass substrates, were designed and manufactured. The feeding line and radiating and ground planes were formed using conductive (copper) tape. The operating frequency range of the antenna was chosen between 2 GHz and 10 GHz, and the simulated gain of the antenna was obtained as 5.31 dB. The measurement S11results demonstrate that the results are in good agreement with the simulated ones. The proposed antenna allows continuous monitoring of patients at high risk of cancer. © 2021 IEEE.
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    Designs of three different octagonal-shaped antennas for microwave-based breast cancer detection
    (Iop Publishing Ltd, 2023) Aydin, Emine Avsar; Aydin, Ahmet; Saribas, Gozde
    Today, there are numerous studies on Microwave Imaging Methods. Thanks to these studies, the success and accuracy rate, especially in breast cancer diagnosis, increases. Microstrip antennas are used in the microwave imaging method. In this study, three different antenna models aimed to be used in microwave imaging methods were designed on the CST Studio Suite program. The designed antennas have been tested on the phantom model in the simulation environment. The test results were examined, and the designed antennas were produced using 3D printing technology. The built antennas were tested in the laboratory using the phantom and tumor-containing phantom models and obtained results were compared.
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    Electromagnetic and Chemical Analysis and Performance Comparison of Inset-fed Rectangular Microstrip Antennas
    (Wiley-V C H Verlag Gmbh, 2023) Aydin, Emine Avsar; Bicer, Mustafa Berkan; Mert, Mehmet Erman; Mert, Basak Dogru
    A simple method for creating lightweight and inexpensive microstrip patch antennas using reduced graphene oxide or acetylene black added epoxy resin was developed. The biggest goal in the method is optimizing the appropriate chemicals and production processes for producing the materials with the designed properties. Five examples of an inset-fed microstrip patch antenna operating at approximately 2.0-12.0 GHz were designed based on the antenna's basic analytical formula. Their models were created in a 3D electromagnetic simulation environment. After examining the performance results of the design, the appropriate design models were produced with both 3D printer technology and wet-chemical methods, and the experimental results were compared with the simulation results. The produced reduced graphene oxide or acetylene black added samples ' structure was illuminated with scanning electron microscope images, FTIR and Raman spectroscopy analysis. The measured S-11 characteristics of the antennas provide better performance as compared to the simulated results. The measured S-11 parameters for the two and three frequency bands fell substantially below -10 dB. As a result of the dielectric constants of the materials and the fabrication of the radiation plane, horizontal shifts were detected in the measurement outcomes.
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    Low-cost saw/sinus-tooth-shaped circular microstrip patch antenna for in-space and satellite applications
    (Iop Publishing Ltd, 2024) Aydin, Emine Avsar; Akbiyik, Hurrem
    Antennas operating in S and C bands are crucial in space satellite applications due to their high bandwidth, which facilitates the swift transmission of large data volumes from space vehicles to Earth. These bands are less affected by atmospheric disturbances and exhibit lower noise levels, ensuring uninterrupted and reliable communication between spacecraft and Earth centers. They are essential for satellite-based remote sensing, analyzing surface properties, transmitting high-resolution images, scientific data, and other information. Additionally, they are used for spacecraft control and navigation, enabling precise mission operations. This study emphasizes user-friendly production antennas with different geometries and distinct feeding techniques, demonstrating various design implementations using CST Microwave Studio software. Innovative manufacturing methods such as 3D printing PLA substrates and using copper tape for antenna elements were explored to optimize costs and production processes. Precise cutting of antenna radiation geometries was achieved using the Cricut machine. Experimental validation through reflection coefficient (S11) measurements with a handheld vector network analyzer confirmed the practical application of theoretical foundations. The study's novelty lies in examining unconventional materials like PLA filament for antenna substrates, exploring fractalization theory for enhancing bandwidth, and discussing advancements in material science with flexible filaments like TPU. These contributions offer insights into user-friendly antenna production, innovative manufacturing techniques, and theoretical explorations in antenna design, enhancing the efficiency and effectiveness of space satellite communication systems.
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    Multilayer Perceptron Approach to Different Parameter Bow-tie Antennas Produced with PLA / Carbon / Copper Mixtures
    (Institute of Electrical and Electronics Engineers Inc., 2020) Saribas, Gozde; Aydin, Emine Avsar; Torun, Ahmet Refah
    The study aims to observe the operating efficiency of seven different Bowtie Antennas produced with PLA/Carbon mixture material under the desired conditions. The constructed antennas' desired feature is that the return loss (s11) in the low-frequency range is -10dB and below. This value is that the antenna's s11 value is of great importance in detecting the tumor in the breast tissue. Parameters of antennas are the antenna substrate's thickness, the antenna substrate area, and the antenna legs' length. With these parameter values, s11 data were obtained in the frequency range 0-3 GHz. Another purpose of the study is to observe the effect and accuracy of the parameters used based on the return loss estimation of the designed antennas. The data obtained were evaluated using the Multilayer Perceptron approach. © 2020 IEEE.
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    Multilayer Perceptron Approach to PLA, PLA /Copper and PLA / Carbon Substrate Bow-tie Antenna Production
    (Institute of Electrical and Electronics Engineers Inc., 2020) Saribas, Gozde; Aydin, Emine Avsar; Torun, Ahmet Refah
    The study aims to observe the operating efficiency of Bowtie Antennas produced with three different materials under the desired conditions and to compare between materials. The produced antennas' desired feature is that the return loss (s11) in the low-frequency range is -10dB and below. This value is that the s11 value of the antenna is of great importance in detecting the tumor in the breast tissue. Parameters of antennas produced with different materials; The dielectric coefficient of the material used is the antenna diameter, the antenna substrate's thickness, and the length of the antenna legs. With these parameter values, s11 data at different frequency values in the frequency range of 0-3 GHz were obtained. Another purpose of the study is to observe the effect and accuracy of the parameters used on the result of the return loss estimation of the designed antennas. The data obtained were evaluated using the Multilayer Perceptron approach. © 2020 IEEE.
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    Reference Breast Phantoms for Low-Cost Microwave Imaging
    (Univ North, 2020) Aydin, Emine Avsar; Karaoglan, Selin Yabaci
    Microwave imaging provides an alternative method for breast cancer screening and the diagnosis of cerebrovascular accidents. Before a surgical operation, the performance of microwave imaging systems should be evaluated on anatomically detailed anthropomorphic phantoms. This paper puts forward the advances in the development of breast phantoms based on 3D printing structures filled with liquid solutions that mimic biological tissues in terms of complex permittivity in a wide microwave frequency band. In this paper; four different experimental scenarios were created, and measurements were performed, and although there are many vector network analyzers on the market, the miniVNA used in this study has been shown to have potential in many biomedical applications such as portable computer-based breast cancer detection studies. We especially investigated the reproducibility of a particular mixture and the ability of some mixes to mimic various breast tissues. Afterwards, the images similar to the experimentally created scenarios were obtained by implementing the inverse radon transform to the obtained data.
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    THE EFFECTS OF DIELECTRIC VALUES, BREAST AND TUMOR SIZE ON THE DETECTION OF BREAST TUMOR
    (Univ North, 2019) Uncu, Nusin; Aydin, Emine Avsar
    Although breast cancer is the second main cause of female deaths after lung cancer, early diagnosis plays a crucial role to diminish the death rate. Many techniques have been improved to detect the cancerous cells. At different microwave frequencies, the malignant cells indicate different electrical characteristics as compared to the normal cells. According to these frequencies, the breast tissue is more permeable than other tissues such as the brain and muscle. Due to this property of the breast tissue, microwaves can be used for the detection of breast cancer. In this study, the breast prototype was modelled using the CST STUDIO SUITE electromagnetic simulation software with respect to different breast size, tumor size and dielectric values tested at a range of the 0-3.0 GHz frequency. The objective of this paper is to investigate the effects of each factor and the interactions of factors on detecting cancer cells using the factorial analysis. The results indicate that the factors such as fat and skin permittivity, tumor and breast sizes are more effective in the detection of breast tumor. Although the effect of fibro permittivity is not significant alone, there are considerable interaction effects of a large breast size and small tumor size through low-to-high values of fibro permittivity. Furthermore, the combinations of a breast radius smaller than almost 8.5 cm with a high level tumor radius and breast radius larger than 8.5 cm with a low level tumor radius are desirable for lessening the return loss value.
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    UWB Rectangular Microstrip Patch Antenna Design in Matching Liquid and Evaluating the Classification Accuracy in Data Mining Using Random Forest Algorithm for Breast Cancer Detection with Microwave
    (Springer Singapore Pte Ltd, 2019) Aydin, Emine Avsar; Keles, Mumie Kaya
    The most common type of cancer for a female is breast cancer in the world. Regular checks and effective-timely treatment are noteworthy parameters for patients' survival struggle . Against existing imaging methods, microwave imaging method has been considered more powerful and effective method by many researchers. In this paper, comprehensive design equations and parameters of rectangular microstrip patch antenna (RMPA) are given for microwave breast cancer detection. The layered breast model with a spherical tumor that was placed into the fibro-glandular layer was created by using CST Microwave Studio Software, and it was embedded in canola oil to decrease the distorted signals between the transmitting and receiving antennas. The RMPA has a wideband performance from 3 to 18GHz. The simulation results show that differences in the electric field and reflection coefficients might more efficiently give a possibility to assign the tumor in the breast model. In addition, in this study, the data obtained from these experiments are classified by using the random forest algorithm from the data mining methods. According to the classification result, the random forest algorithm can diagnose breast cancer by classifying the tumor as 94% accuracy.