Person: YALÇIN, UĞUR
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YALÇIN
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UĞUR
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Publication Scattering from perfectly magnetic conducting surfaces: The extended theory of boundary diffraction wave approach(Electromagnetics Acad, 2009-01-01) Yalçın, Uğur; YALÇIN, UĞUR; Elektronik Mühendisliği; AAG-8951-2021In this paper, the uniform scattered fields from a perfectly magnetic conducting (PMC) surface are studied with the extended theory of boundary diffraction wave (TBDW). The vector potential is described by considering the extended TBDW for the PMC surfaces. The extended TBDW is then applied to the problem of scattering from the PMC half plane. The total scattered fields are obtained and compared numerically with the exact solution for the same problem. The numerical results show that the solution of the extended TBDW is very close to the exact solution.Publication Uniform scattered fields from a parabolic surface with the boundary diffraction wave theory(Photonics Soc Poland, 2017-01-01) Yalçın, Uğur; Altıngöz, Can; YALÇIN, UĞUR; Mühendislik Fakültesi; Elektrik Elektronik Mühendisliği Bölümü; AAG-8951-2021Uniform scattered fields of a cylindrical wave from a parabolic surface are obtained with the theory of the boundary diffraction wave (TBDW). A non-uniform diffracted field is calculated with a regenerated vector potential and rearranged by considering the Fresnel function to obtain a uniform solution. Uniform scattered fields are calculated as the sum of diffracted and geometrical optic fields. Numerical analyses of diffracted and scattered fields in both uniform and non-nuniform solutions are in harmony with the literature.Publication Uniform scattered fields of the extended theory of boundary diffraction wave for pec surfaces(Electromagnetics Acad, 2009-01-01) Yalçın, Uğur; YALÇIN, UĞUR; Elektronik Mühendisliği Bölümü; AAG-8951-2021In this paper, the uniform scattered fields from a perfectly conducting (PEC) half plane are studied with the extended theory of the boundary diffraction wave. A new vector potential of the boundary diffraction wave is found by considering the Fermat principle for the PEC surfaces. This vector potential is applied to the Helmholtz Kirchhoff integral, and the theory of the boundary diffraction wave is extended to the PEC surfaces. The extended theory of the boundary diffraction wave is then applied to the scattering problem for the PEC half plane. The total scattered fields are compared numerically with the exact solution for the same problem. The numerical comparisons given in the paper show that the solution of the extended theory of the boundary diffraction wave is very close to the exact solution.Publication Developing a real-time working method that improves process efficiency in high-power fiber laser systems(MDPI, 2022-09-01) Yalçın, Uğur; Karanfil, Uğur; YALÇIN, UĞUR; Elektrik Elektronik Mühendisliği Bölümü; 0000-0002-4160-9774; CGN-0712-2022The need for studies on new simulation and monitoring methods for interactions occurring during material processing in high-power fiber laser systems has increased. In this manuscript, a structure that can intervene in real time and improved solutions that demonstrate the potential of photodiode-based monitoring are presented. By processing the signals instantly received during material processing with InGaAs and Si photodiodes integrated into the cutting head in algorithms, the method that intervenes in the process by detecting the last stage of the piercing process and the problems that may occur during cutting are explained. The stability of the proposed system has been tested on the most used materials in the industry such as St37, stainless steel, and aluminum at laser powers of 6, 8, and 10 kW, respectively. In this article, it is shown that there is a relationship between the signals observed in the infrared (IR) and visible (VIS) spectrum and the characteristics of the cut quality and scenario. Analysis results of photo-diode tracking signals obtained according to material, power, and gas type are presented. Among the innovations added by the method are related application process improvements, material analysis, and cutting and piercing parameter improvements.Publication C-Bandında frekans seçici yüzey tasarımı ve analizi(Bursa Uludağ Üniversitesi, 2023-07-28) Barış, Yağmur; Yalçın, Uğur; YALÇIN, UĞUR; Elektrik Elektronik Mühendisliği Bölümü; 0000-0002-0303-0198Belirlenen frekans aralığında yüzeye gelen elektromanyetik dalgaların iletim, yansıma veya soğurma özelliği göstermesini sağlayan periyodik yapılara frekans seçici yüzeyler (FSY) denir. Çalışmada üç farklı geometrik şekle sahip FSY tasarlanmıştır. Tasarlanan yapıların temel iletim karakteristiğini bozmadan, birim hücreleri üzerinde optimizasyon çalışmaları yaparak, kullanılan parametrelerin değiştirilmesinin, s parametreleri, rezonans frekansı, bant genişliği ve maksimum soğurma değerine etkisi incelenmiştir. Cbandında (4 GHz–8 GHz) gerçekleştirilen çalışmalarda -10 dB kazanç değerinde bant genişliğini arttırabilmek için tasarlanan iki yapının üst üste birleştirilmesiyle yeni bir ultra geniş bantlı (UGB) FSY elde edilmiştir. Elde edilen yeni UGB FSY ile radar kesit alanının (RKA) azaltılması amaçlanmıştır. Tasarıma ait benzetim ve analizler CST Studio Suite 3D programı ile gerçekleştirilmiştir.Publication Modified theory of physical optics and related applications(Int Frequency Sensor Assoc-ifsa, 2019-01-01) Yurish, SY; Sarnık, Mücahit; Yalçın, Uğur; YALÇIN, UĞUR; Mühendislik Fakültesi; Elektrik ve Elektronik Mühendisliği Bölümü; Yurish, SY; AAG-8951-2021The scattering problem from the surfaces is introduced by method of Modified Theory of Physical Optics (MTPO). The method is based on the physical optics (PO) current, on the scaterers' and aperture surfaces, which assist in finding the integral equation and the evaluation is achieved asymptotically with the stationary phase method. The comparisons, on various surfaces, prove the agreement of the MTPO with respect to the exact solution of Helmholtz equation. MTPO can be applied to calculate not only the reflected fields but also to calculate edge diffraction fields of various surfaces such as perfectly electrically conducting (PEC), impedance and black surfaces.