Kocakarin, I. | Yegin, K.
Conference Object | 2017 | 2017 4th International Electromagnetic Compatibility Conference, EMC Turkiye 2017
Signal penetration into missiles through nose cone and apertures is critical for electro-optical guidance systems, navigation equipment and control of explosive ordnance. Penetrated signals are relatively small but hard to simulate by known computational methods. To corroborate simulation results, we created a scaled version of a missile and placed wire antennas inside this mock missile. The prototype has openings on the nose cone. Measurements are performed for different antenna sizes placed inside the nose cone. These measurements, then, are compared to numerically calculated simulation results. The extent of corroboration and pos . . .sible ways to improve correct prediction of signal coupling are discussed. © 2017 IEEE
Icin, O. | Yegin, K.
Evolution of modern communications and radar systems have steadily increased the demand on modelling the propagation effects with real world scenarios for various signal types. The main purpose of this research is to create a flexible, generic and realistic Radio Frequency (RF) environment simulator including both radar and communication signals. Software defined radio (SDR) platform has been utilized for generating the simulated signals at radio frequencies. Power and delay profiles, frequency selective fading, Doppler effect and noise have been calculated for multiple paths and generated via RF outputs of the SDR. RF outputs of th . . .e system is suitable for use in the tests of receivers like direction finding systems and LTE MIMO systems. Communication quality for various terrain profiles and fading scenarios has been experimentally investigated for several signal types using vector signal generators, vector signal analyzers, demodulation and communication analysis tools. This simulation platform can be used in Electromagnetic Compatibility tests of such systems as well. © 2017 IEEE
Ozturk, H. | Nazli, H. | Yegin, K. | Sezgin, M.
Article | 2012 | International Journal of Photoenergy2012
Detection of ammonia plays a vital role for counter-bioterrorism applications. Using millimeter wave absorption measurements, ammonia dissolved in water solution is analyzed and compared to water-only solution. The inversion of ammonia molecule results in split rotational spectral lines and transitions of these lines can be detected. Two-port measurements were carried out with vector network analyzer and measurements revealed that ammonia presence can be identified, especially between 3035 GHz. © 2012 Hilmi Ozturk et al.
Dasdag, S. | Taş, M. | Akdag, M.Z. | Yegin, K.
Article | 2015 | Electromagnetic Biology and Medicine34 ( 1 ) , pp.37 - 42
The aim of this study was to investigate long-term effects of radiofrequency radiation (RFR) emitted from a Wireless Fidelity (Wi-Fi) system on testes. The study was carried out on 16 Wistar Albino adult male rats by dividing them into two groups such as sham (n: 8) and exposure (n: 8). Rats in the exposure group were exposed to 2.4 GHz RFR radiation for 24 h/d during 12 months (1 year). The same procedure was applied to the rats in the sham control group except the Wi-Fi system was turned off. Immediately after the last exposure, rats were sacrificed and reproductive organs were removed. Motility (%), concentration (× 106/mL), tail . . . defects (%), head defects (%) and total morphologic defects (%) of sperms and weight of testes (g), left epididymis (g), prostate (g), seminal vesicles (g) were determined. Seminiferous tubules diameter (mm) and tunica albuginea thickness (µm) were also measured. However, the results were evaluated by using Johnsen's score. Head defects increased in the exposure group (p<0.05) while weight of the epididymis and seminal vesicles, seminiferous tubules diameter and tunica albuginea thickness were decreased in the exposure group (p<0.01, p<0.001, p<0.0001). However, other alterations of other parameters were not found significant (p?0.05). In conclusion, we observed that long-term exposure of 2.4 GHz RF emitted from Wi-Fi (2420 µW/kg, 1 g average) affects some of the reproductive parameters of male rats. We suggest Wi-Fi users to avoid long-term exposure of RF emissions from Wi-Fi equipment. © 2015 Informa Healthcare USA, Inc
Bilgiç, M.M. | Yegin, K.
Article | 2013 | International Journal of Distributed Sensor Networks2013 , pp.37 - 42
Polarization reconfigurable microstrip patch antenna is presented for 2.4-2.5 GHz wireless sensor network and WLAN applications. Dual feed degenerate mode patch is used as the starting point for circular polarization and L-shaped islands which can be connected or disconnected to the main patch via RF switches are placed around the patch. When L-shape structure is connected, the patch radiates in linear polarization modes with either vertical or horizontal polarization depending on the feed being used. When RF switches are not biased, the antenna is in circular polarization mode. Full wave simulations and measurements were carried ou . . .t to validate the design. © 2013 Mustafa Murat Bilgiç and Korkut Yegin
Bayrakceken, F. | Yegin, K. | Korkmaz, E. | Bakis, Y. | Unal, B.
Article | 2012 | International Journal of Photoenergy2012 , pp.37 - 42
Optical energy transfer from naphthalene to biacetyl in liquids at room temperature is studied. Electronically excited naphthalene with 200-260 nm ultraviolet (UV) light emits photons in its emission band and the emitted photons are absorbed by biacetyl, which, in turn, excites biacetyl phosphorescence. The resulting phosphorescence is very stable with emission peak at 545 nm for different excitation wavelengths from 200 to 260 nm. Similar optical energy transfer is also observed from pyrazine to biacetyl. The sensitization of biacetyl by several aromatic donors has been investigated in detail. An aromatic donor, pyrazine, is raised . . . to its first excited singlet state by absorption of ultraviolet radiation. Excitation wavelengths were selected in the first n-? band of pyrazine. Intersystem crossing in pyrazine is sufficiently fast to give a triplet yield of almost unity as determined by the biacetyl method. The optical excess energy in the biacetyl will be released as light, which is sensitized fluorescence. Biacetyl is the simplest molecule among a wide range of ?-dicarbonyl compounds, which is important for photophysics and photochemistry applications. © 2012 Fuat Bayrakceken et al
Yegin, K. | Karaaslan, Ş.I. | Aslan, N.
Editorial | 2012 | International Journal of Photoenergy2012 , pp.37 - 42
[No abstract available]
Polycyclic aromatic hydrocarbon compound, 1,2: 3,4-dibenzanthracene, is spectroscopically analyzed in ethanol. Ultraviolet absorption spectra were taken and fluorescence measurements were performed. From absorption and emission spectra, Stokes' lines were clearly discernible and these shifts were recorded. Being a carcinogenic compound, the detection of 1,2: 3,4-dibenzanthracene presence in the environment as a pollutant with adverse genotoxic effects is vital. © 2012 Fuat Bayrakceken et al.
Article | 2012 | EDN57 ( 11 ) , pp.47 - 48
Korkmaz, E. | Araz, I. | Dursun, A. | Yegin, K.
Conference Object | 2011 | 2011 30th URSI General Assembly and Scientific Symposium, URSIGASS 2011 , pp.47 - 48
This paper discusses the design considerations of a 10 GHz helix traveling wave tube using commercial electromagnetic simulation software CST-PIC/MWS. The dispersion characteristics of the TWT have been analyzed by modeling of a single turn electron-free slice in eigenmode solver. The return loss optimization of the input-output couplers is performed by using of transient solver. The complete model has been simulated and analyzed in particle-in-cell solver and the results are presented. © 2011 IEEE.
Bayrakceken, F. | Yegin, K.
Article | 2012 | International Journal of Photoenergy2012 , pp.47 - 48
Spectroscopically pure fused silica has been used in many applications ranging from optoelectronics and optical fibers to laser flash spectroscopy. Although ultraviolet light irradiated optical absorption spectra and coherence fluorescence of silicon dioxide have been studied in the past, we present discrete absorption and resonance coherent fluorescence line of silicon dioxide which were recorded photographically at 288.2 nm. This discrete fluorescence is observed at room temperature using high photon flux (1024 photon/pulse) excitation spectroscopy. © 2012 Fuat Bayrakceken and Korkut Yegin.
Koc, G. | Yegin, K.
Article | 2013 | International Journal of Distributed Sensor Networks2013 , pp.47 - 48
Seismic sensors are invaluable for intruder detection and perimeter security. In a typical wireless sensor network application of seismic sensors, the units are battery powered and low power consumption becomes critical while fulfilling system requirements. Although many systems utilize 24-bit ADC for seismic signal processing, we employed 12-bit ADC for low power consumption. Because of this relatively low resolution ADC, preamplifier and filters require careful hardware design. We employ bidirectional T-type filtering, noise reduction, and distributed filtering between gain stages before the signal is input to ADC. The proposed de . . .sign was verified with measurements. Seismic data signals due to footsteps at varying distances were successfully measured. © 2013 Gokhan Koc and Korkut Yegin