Nassor, M.A. | Korkmaz, E. | Yegin, K.
Conference Object | 2014 | 2014 31th URSI General Assembly and Scientific Symposium, URSI GASS 2014
Planar antennas such as microstrip patch, bowtie, spiral, and modified crossed dipole are designed and simulated at 30 THz. Gains of antennas obtained directly from simulation results are verified using a different technique inspired from radar cross section measurements. Reradiated far field of an antenna when its feed point is open-circuited is obtained with a far-field probe. The proposed method is introduced as an alternative for the signal detection sensitivity measurements of IR detector antennas. © 2014 IEEE.
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
Yigit, O. | Asci, Y. | Sissman, I. | Yegin, K.
Conference Object | 2017 | 24th Telecommunications Forum, TELFOR 2016
We propose a low-cost solution for jamming mitigation of GPS by electronically switching antenna beam. Jamming signals are assumed to be directed from low elevation angles so that antenna rejection from zenith to low elevation must be improved by switching from wide angle half power beam width to a narrow one. Using low-cost, commercially available ceramic patches, four-element antenna array and its feed network are designed and one of the elements is designated as the normal (default) mode operation of the antenna. Proposed system can easily be replaced with existing active antenna to improve anti-jam capability of the receiver. © . . .2016 IEEE
Article | 2013 | IEEE Transactions on Antennas and Propagation61 ( 9 ) , pp.4775 - 4782
A diversity antenna system with antennas embedded in rear view mirrors of a vehicle is proposed for satellite digital audio radio system. Antenna diversity is needed because hidden antennas exhibit limited capability and composite body vehicles have poor reception due to no ground plane availability. Pattern gain diversity achieved with the proposed system is proven with on-vehicle antenna simulations and gain measurements. Selection combining diversity receiver architecture is also proposed and the system is tested in real time under two fading scenarios: weak satellite signal in dense foliage and multipath terrestrial environment . . .with frequent satellite blockages. In both cases, the diversity system outperformed the reference antenna system with less mutes times (0.6% versus 0.8% in multipath, 0.1% versus 0.25% in dense foliage) and Reed-Solomon block errors (1.75% versus 2.18% in multipath, 0.87% versus 1.18% in dense foliage). The proposed rear-view mirror location is ideal for minimum signal degradation compared to windshield, backlite, and dashboard antenna installations. © 1963-2012 IEEE
Icin, O. | Yegin, K.
Conference Object | 2017 | 2017 4th International Electromagnetic Compatibility Conference, EMC Turkiye 2017 , pp.4775 - 4782
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
Bilgic, M.M. | Yegin, K.
Article | 2014 | IEEE Transactions on Antennas and Propagation62 ( 4 ) , pp.2258 - 2263
Wideband, planar and low profile antenna array is proposed and designed for Ku band direct broadcast from satellite reception for mobile systems. Contrary to earlier designs, the array antenna covers entire downlink Ku-band frequencies (10.8-12.75 GHz) for simultaneous reception from multiple transponders. The array antenna exhibits 16.5% bandwidth and has 30 dBi average gain for both vertical and horizontal polarizations. To achieve high efficiency, hybrid waveguide microstrip feed network is proposed. H-plane waveguide T-junctions with reduced waveguide height and disk loaded coaxial probe for microstrip to waveguide transition ar . . .e designed. Loss in the array is formulated as an optimization problem and it is minimized for subarray and array configuration. Overall height of the planar antenna with waveguide feed network is under 25 mm. The antenna is built and tested for reception quality. Carrier-to-noise ratio of 9.5 dB was observed for the target transponder (42°E) at 11.9 GHz using IF loop-out of the receiver. © 1963-2012 IEEE