17 results
Search Results
Now showing 1 - 10 of 17
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.Conference Object A Bayes decision model for RSS based location estimation(Ieee, 2007) Dincer, Zeynep; Oektem, Rwen; Aydin, ElifThis work introduces a location estimation method based on Bayes Decision Theory using Radio Signal Strengths for indoor environment. Signal Strengths are observed through three transmitters at three distinct frequencies in UHF band, an active RFID tag and a modem connected to a computer. The test environment is 2100cmx720cm, which is divided into classed of square grids. For each class, a set of received signal strengths are measured and processed. Assuming that the class in which the RFID tag was located in the previous time of measurement is known, the next location (class) is estimated using Bayes Decision Theory. Proposed method is tested in a laboratory environment with obstacles. Results show that proposed method will be successful in location estimation where the estimation error stays within around 2m.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 Analysis of the Parameters That Effects the Operating Frequencies and Bandwidth of a Cpw-Fed Patch Antenna(Ieee, 2013) Dagdeviren, Birkan; Kapusuz, K. Yavuz; Can, Sultan; Aydin, ElifIn this study, the analysis of the effect of antenna parameters to the operating frequency is performed in a coplanar waveguide fed patch antenna. The effect of the size and the substrate of the design dual frequency antenna to the operating frequency and bandwidth are also evaluated. Bandwidth of the upper and lower frequency is also investigated and results are demonstrated. The method to increase the bandwidth is also presented by using the chosen parameters.Conference Object COMPARISON OF COMPUTER-BASED PROPAGATION MODELS WITH EXPERIMENTAL DATA COLLECTED IN AN URBAN AREA AT 1800 MHz(Ieee, 2015) Acar, Tarik; Caliskan, Fatma; Aydin, ElifNowadays a lot of models are set for the efficient and economic usage of frequency band since the band is a limited source. Therefore, the propagation models created for this purpose were studied in the literature. These models are Free Space Path Loss (Fspl) + Reflection plus Multiple Diffraction (RMD), COST-Hata and COST-WI models. In order to compare the success of the models, electric field strength measurements were taken in a chosen district (Mustafa Kemal Mahallesi Ankara, Turkey) where an irregular structure style can be observed. First set of measurements were recorded at random coordinates and second set of measurements were collected by the following coordinates tracking on a single line. As a conclusion, measured values were compared with the results which were taken from the mentioned models with graphical presentations. The most appropriate model was tried to be found and as another aim of the study, a correction factor was generated as a modification for COST-Hata propagation model.Conference Object Citation - WoS: 1Design and Analysis of Rectangular Dielectric Rod Antennas(Ieee, 2015) Demir, Mahmut; Ozkok, M. Aybars; Caliskan, Fatma; Aydin, ElifIn this study, rectangular dielectric rod antennas with different dimensions and different shapes are designed and analyzed using HFSS simulation software. To analyze the effects of these changes, five different antennas are designed and antenna gains and return loss values are compared.Conference Object Citation - Scopus: 2Uav Detection and Ranging With 77-81 Ghz Fmcw Radar(Ieee, 2022) Doganay, Bengisu; Arslan, Mustafa; Demir, Efe Can; Coruk, Remziye Busra; Gokdogan, Bengisu Yalcinkaya; Aydin, ElifIn this study, detection of unmanned aerial vehicles (UAV), determination of radar cross-section (RCS) values, and range estimation were performed using a commercial off-the-shelf (COTS) millimeter-wave Frequency Modulated Continuous Wave (mmWave FMCW) radar system in the 77-81 GHz frequency band. The measurements were carried out in a laboratory environment using a single transceiver antenna without the need for an anechoic chamber. RCS values of different vertically and horizontally positioned UAVs were measured experimentally along the 360 degrees aspect angle, and the simulated results obtained from computational tool were compared with the experimental results. The measurement and simulation results, together with the range estimation, matched with high accuracy.Conference Object Reader Antenna Design for Rfid Applications(Ieee, 2013) Kaynakoz, Goktug; Kilic, N. Koray; Kapusuz, K. Yavuz; Can, Sultan; Aydin, ElifIn this paper, a coplanar waveguide (CPW) fed microstrip patch antenna is designed on finite element method based simulation program and fabricated in order to use reader antenna in Radio Frequency Identification (RFID). The results of the simulations and the produced antennas are presented in the study. The produced microstrip patch antenna has a 105MHz bandwidth and operates in between 895-1000 MHz.Conference Object Citation - WoS: 1Modelling of the Slotted Rectangular Waveguide Array Antennas(Ieee, 2015) Celik, Aslihan; Serindere, Melih; Ozmen, Zeynep; Caliskan, Fatma; Aydin, ElifIn this study, the slotted rectangular waveguide array (SRWA) antennas' lengths and widths of slots, and the distances between the slots has been changed to observe the radiation properties of the structure. Return loss and radiation pattern graphics of the designs has been obtained using HFSS simulation program. Deviation in resonance frequency and differences in resonance frequency return loss values has been examined on the obtained simulation results.Conference Object An Indoor Navigation Aid Designed for Visually Impaired People(Ieee, 2008) Oktem, Rusen; Aydin, Elif; Cagiltay, Nergiz ErcilThis work introduces the hardware architecture and general principles of a portable indoor navigation system for guiding visually impaired people. It operates through wireless communication between a compact hardware interface unit carried by the user, a central processing unit and an active RFID unit. The RFID unit collects signals as regard to the position of the user, the central system processes those signals to estimate the position of the user and proposes a route and direction for the user to follow, whereas hardware interface unit provides interaction. The orienteering of the user is obtained by a tactile compass.
