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Conference Object Citation - WoS: 2Citation - Scopus: 3Design Considerations for Sub-Ghz Multilayer Microstrip Antenna for Near Ground Communication Links in Rural Areas(Ieee, 2017) Bilgin, Gulsima; Yilmaz, Vadi Su; Aydin, Elif; Kara, Ali; Department of Electrical & Electronics Engineering; Electrical-Electronics EngineeringThis paper presents some preliminary results of design and development of sub-GHz multilayer microstip antenna for use in near ground communication applications. In design stage of the antenna, iterative approach was applied. Firstly, a two layer microstrip antenna design process is presented. Next, the corners of the patch were cut, and a vertical wall on all sides of the antenna were introduced. In this way, both the size and resonant freqeuncy can be tuned. Moreover, as an application specific requirement, it is intended to embed this antenna into a metal box in order to protect it from man-made and natural environmental effects. This was also studied, and effects of the embedding ground on the antenna characteristics were examined. It is shown that the designed antenna provides -27dB resturn loss, and 7.3dB peak gain at 915MHz with the dimension of 150x200x13mm. Some preliminary measurements have proven the simulations.Conference Object Microstrip Antennas For WiMAX Applications(Ieee, 2015) Demirci, Tugkan; Caliskan, Fatma; Aydin, ElifIn this paper, four different antenna types have been designed to be used for WiMAX applications. These antennas have been designed using HFSS simulation software. This paper has included the return loss and the radiation pattern of the designed antennas. Using the simulation results, it is shown that these four antennas are working on Wi-Fi and WiMAX frequency ranges.Article Citation - WoS: 1Citation - Scopus: 3Calculation of Resonant Frequencies of a Shorting Pin-Loaded Etma With Ann(Wiley-blackwell, 2014) Can, Sultan; Kapusuz, Kamil Yavuz; Aydin, Elif[No Abstract Available]Conference Object Citation - WoS: 17Citation - Scopus: 23Maintenance, Sustainability and Extendibility in Virtual and Remote Laboratories(Elsevier Science Bv, 2011) Kara, Ali; Ozbek, Mehmet Efe; Cagiltay, Nergiz Ercil; Aydin, ElifThis study presents discussions on sustainability of Virtual and Remote Laboratories (VRL), and provides challenges toward maintenance of VRLs. Technical and pedagogical issues in extension and sustenance of VRLs are discussed with the experiences of the authors gained in the development of a VRL system, European Remote Radio Laboratory (ERRL) platform. Moreover, the study presents actions to be taken in sustenance plan and expendability of VRL system with the advances in Information and Communication Technologies (ICT) and educational technologies along with the needs of educators and learners in formal education. (C) 2011 Published by Elsevier Ltd.Conference Object Study of an Rfid Based Moving Object Tracking System(Istanbul Technical Univ, 2007) Aydin, Elif; Oektem, Rusen; Dincer, Zeynep; Akbulut, I. KaanThis paper presents a study on localization and tracking of an object carrying an active RFID tag. The study incorporates processing of the signals received from transmitters.. in a way to locate and track the coordinate in an indoor environment. During the course of the project,, both outdoor and indoor experiments have been conducted. Empirical distance vs signal strength formulations are formed by use of the collected data. Deviation of the reported values from the theory is analyzed, and the effects of reflections from doors. windows, etc. are observed. In order to improve the accuracy of tracking, Bayesian and Kalman Filtering approaches are incorporated.Article Citation - WoS: 6Citation - Scopus: 9Comparative Assessment of Electromagnetic Simulation Tools for Use in Microstrip Antenna Design: Experimental Demonstrations(Wiley, 2019) Bilgin, Gulsima; Yilmaz, Vadi Su; Kara, Ali; Aydin, ElifThis paper presents a better understanding of the use of finite integration techniques (FIT) and finite element method (FEM) in different types of microstrip antennas in order to determine which numerical method gives relatively more accurate results. Although the theoretical formulation based on Maxwell's equations of both FEM and FIT are approached from different aspects in the literature, there is still a lack of comparison of the same antenna type using different numerical methods employing FEM and FIT. Therefore, in this study, FEM and FIT were applied to two different types of microstrip antennas, and their simulation and experimental results was compared. For the first antenna demonstration, a multilayer structure was chosen to achieve one of the significant parameters. Then, a microstrip antenna with a compact structure was used in the second demonstration. Using these two antennas, the accuracy of FEM and FIT in different structures were compared and all simulated return loss and gain results were verified by the measured results. The experimental demonstrations show that FEM performs better for both types of microstrip antennas while FIT provides an adequate result for two-layer microstrip antennas.Article Citation - WoS: 8Citation - Scopus: 8A New Rf and Microwave Engineering Course Enriched With Advanced Technologies(Wiley, 2012) Aydin, Elif; Cagiltay, NergizIn this study, a curriculum model including recent developments and technologies in the Radio Frequency (RF) and Microwave Engineering field by using a blended approach is proposed. This study covers the description of the content of theoretical and hands on applications, the integration model of the technological tools into the proposed curriculum, and the instructional approaches used in the new course design. The main goal of the course is to prepare students for future professional careers in RF and Microwave Engineering by supporting them with new instructional technologies. The secondary goal of the course is to better prepare the students for the sequence of senior courses in the Electrical and Electronics Engineering program of Atilim University. The course is structured with a balance between theory and laboratory, including remote and in lab measurement experiments as well as modeling and designing microwave components by means of computer tools and design fabrication. The newly designed course is implemented at the Atilim University. The study also reports the first semester implementation. (C) 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 634645, 2012Article Citation - WoS: 17Citation - Scopus: 22Seven Principles of Instructional Content Design for a Remote Laboratory: a Case Study on Errl(Ieee-inst Electrical Electronics Engineers inc, 2011) Cagiltay, Nergiz Ercil; Aydin, Elif; Aydin, Cansu Cigdem; Kara, Ali; Alexandru, MarianThis paper discusses the results of a study of the requirements for developing a remote radio frequency (RF) laboratory for electrical engineering students. It investigates students' preferred usage of the technical content of a state-of-the-art RF laboratory. The results of this study are compared to previous findings, which dealt with other user groups (technicians in technical colleges and engineers in the RF domain). Based on the results of these analyses, seven essential principles for designing and developing such a laboratory were identified. As a case study, these principles were then implemented into a remote laboratory system. In this paper, the implementation examples are also provided and discussed. The primary aim of this study is to guide remote laboratory platform developers toward the most effective instructional design. This study also determined, from the remote laboratory system case study, what the requirements are of such a laboratory from the students' perspective.Article Citation - WoS: 8Citation - Scopus: 12Computation and Optimization of Resonant Frequency and Input Impedance of a Coax-Fed Circular Patch Microstrip Antenna(John Wiley & Sons inc, 2007) Gurel, Cigdem Seckin; Aydin, Elif; Yazgan, ErdemMicrostrip antennas are important elements of today's wireless communication networks. In their various applications, it is critical to provide wide hand operation around the resonant frequency providing good impedance match between the antenna element and the feed. In this study, new, simple, arid accurate computation of resonant frequency and input impedance of double-layered, coaxial fed circular disk microstrip antenna with air gap is performed. In the analysis, new effective radius and permittivity expressions are used in simple and modified form including modal effects. Then, a new approach is proposed to provide input impedance matching (it resonant frequency via the application of microgenetic algorithm for wide hand operation. The accuracy of theoretical calculations and impedance matching approach are presented for various,structural parameters and operational modes of the antenna. (C) 2007 Wiley Periodicals, Inc.Article Low Signature UAVs: Radar Cross Section Analysis, Simulation, and Measurement in X-Band(Springer London Ltd, 2025) Unalir, Dizdar; Yalcinkaya, Bengisu; Aydin, ElifThe increasing prevalence of unmanned aerial vehicles (UAVs) is driving the development of radar systems capable of detecting them. This hampers the deployment of UAVs in military operations. While radar cross section reduction (RCSR) can be a valuable solution, the research on this subject is inadequate. This paper presents an RCSR approach adopting a shaping technique for UAVs, demonstrating the proposed approach's efficacy through simulations and actual experimental measurements performed in X-Band on a four-legged UAV model. Using electromagnetic computational instruments, the shaping is applied to the designed UAV model with parameter-based simulations, the simulated radar cross section (RCS) values are derived, and the comparative analysis of these instruments is conducted. Experimental measurements are performed in laboratory conditions using a vector network analyzer. Actual measurement results are validated by simulative findings with the examination of the influence of frequency, polarization, and aspect angle on RCS. The demonstrated measuring approach allows cost-effective and easily applicable research on RCS in X-Band, a commonly utilized frequency range in military. An average RCSR of 10 dBsm has been accomplished with the presented shaping approach.
