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Article W-Band RCS Prediction of Small Objects: Comparing Two Widely Used Methods with Experimental Validation(Gazi University, 2025) Kara, Ali; Aydın, Elif; Yardım, Funda Ergün; Sezgin, DenizThis paper compares the accuracy of Shooting and Bouncing Rays and Electric Field Integral Equation methods for Radar Cross Section prediction of small objects at 77-81 GHz band. Existing studies on RCS prediction methods often lack comprehensive comparisons between computational and experimental results, particularly for small objects measured with a 77 GHz radar. This study addresses this gap by presenting an in-depth analysis of both simulation and measurement data. In this work, three targets with varying geometries and materials were measured with a frequency modulated continuous wave radar and simulated using Ansys HFSS and CST Studio Suite. The measurements were performed with a commercial off-the-shelf (COTS) frequency modulated continuous wave radar operating at 77–81 GHz. This study aims to emphasize the importance of considering both efficiency and accuracy when opting for an RCS prediction method. Overall, the outcomes of both methods have largely demonstrated good alignment. It has been noted that, while Shooting and Bouncing Rays method offers promising time-saving advantages, Electric Field Integral Equation method remains a valuable tool for complex geometries where precise results are crucial.Article Citation - WoS: 1Citation - Scopus: 2A Miniaturized Multi-Layer Microstrip Antenna for Linear Wireless Sensor Network Monitoring Systems(Gazi Univ, 2022) Kara, Ali; Aydın, Elif; Benzaghta, Mohamed; Er, Burak; Bilgin, GulsimaThis article presents a sub-GHz ISM band microstrip patch antenna based on the use of multi-layer compact structure, which overcomes the shortcomings of typical microstrip antennas such as low gain and high resonant frequency. The antenna was simulated using an electromagnetic simulator, ANSYS HFSS, and fabricated on two different substrates: RT Duroid 5880 and FR4 epoxy with a compact size of 100 x 100 x 8 mm3 (0.29λ × 0.29λ × 0.02λ). The simulated results of the antenna were then compared with the measured ones, and the two were observed to have a reasonable agreement. The proposed antenna operates in the sub-GHz license-free ISM band (862-875 MHz), with a gain value of 2.92 dB. Two prototypes of the proposed antenna were fabricated and used in a Linear Wireless Sensor Networks (LWSNs) monitoring system. Results show that the proposed antenna is a good candidate for those types of LWSNs systems.Article Citation - WoS: 6Citation - Scopus: 7An Enhanced Course in Digital Communications(Tempus Publications, 2014) Kara, Ali; Cagiltay, Nergiz Ercil; Dalveren, Yaser; Department of Electrical & Electronics Engineering; Software EngineeringToday technological improvements provide several alternatives and opportunities for improving traditional educational systems. However, integrating these technologies in an appropriate and successful way into the curriculum of traditional systems is a challenge. This work presents the enhancements added to an undergraduate course on Digital Communications which is an introductory course offered to senior undergraduates or first year graduate students. The Digital Communications course covers some essential stages in a typical digital communication system, namely, signal formatting such as analog to digital conversion, baseband modulation and bandpass modulation by concentrating on demodulation and detection at the receiver end. The enhancements include computer simulations, web-based simulation tools and remote laboratory experiments along with several out of class activities. The enhancements have improved the course significantly by supporting constructivist and blended learning methods. The improvement to the course was demonstrated over two years, from the student progress assessed from the collated results of the student evaluation forms and a questionnaire on the course learning outcomes, and a comparison of their performance in the written exams. The results show that there is a significant improvement both in the progress and satisfaction of the students on the enhanced course curriculum. This study shows how different technologies have been successfully integrated to the curriculum of Digital Communications course in a higher education organization and concludes its success factors.
