Meslek Yüksekokulları

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Browsing Meslek Yüksekokulları by ORCID "0000-0002-7099-8190"

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    Analytical ETBDW Formulation for Electromagnetic Scattering by Circular Apertures on PMC Surfaces
    (Springer, 2025-12) Altınel, Mustafa; Yalçın, Uğur; 414019
    This study presents and validates a uniform analytical formulation for electromagnetic diffraction from circular apertures on perfect magnetic conductor (PMC) surfaces using the extended boundary diffraction wave (ETBDW) theory. The proposed PMC–ETBDW model incorporates an in-phase reflection coefficient ( = +1) within the boundary kernel, producing a physically continuous and energy-conserving representation of diffracted fields across illuminated, transition, and shadow regions. Expressed through detour parameters and Fresnel-type transition functions, the formulation eliminates phase discontinuities and maintains amplitude normalization consistent with theoretical energy conservation. Numerical evaluations performed for representative aperture radii (a = λ–3λ) and observation distances (r = 3λ–9λ) confirmed the expected 1/r amplitude decay, smooth Fresnel–Fraunhofer transitions, and constructive interference associated with magnetic reflection. Comparative analyses with PEC and opaque boundaries verified that in-phase magnetic reflection enhances on-axis field intensity and preserves phase continuity near the shadow boundary, in full agreement with the dual electromagnetic behavior predicted for PMC interfaces. Beyond its theoretical completeness, the proposed formulation provides a compact and computationally efficient framework for diffraction modeling and hybrid solver integration, offering practical applicability to magnetic coatings, low-RCS reflectors, and metasurface-based structures.
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    DAİRESEL AÇIKLIKTAN OLUŞAN TOPLAM ALANLARIN KARAKTERİZASYONU: OPAK, PEC VE PMC YÜZEYLER İÇİN KARŞILAŞTIRMALI ANALİZ
    (Bursa Uludağ Üniversitesi, 2026-01) Altınel, Mustafa; Yalçın, Uğur; 414019
    Bu çalışma, dairesel bir açıklıktan yayılan toplam alanların Opak, Mükemmel Elektrik İletken (PEC) ve Mükemmel Manyetik İletken (PMC) yüzeylerdeki davranışlarını karşılaştırmalı olarak incelemektedir. Toplam alan hesaplamalarında Sınır Kırınım Dalgası Teorisi (SKDT) ile Genelleştirilmiş SKDT (GSKDT) yöntemleri kullanılmış, analizler, Miyamoto ve Wolf tarafından tanımlanan vektör potansiyeli temeline dayandırılmıştır. Elde edilen non-uniform toplam alan ifadeleri, Detour parametresi ve Fresnel fonksiyonunun asimptotik özellikleri kullanılarak uniform forma dönüştürülmüştür. Opak yüzeylerde yalnızca gelen dalga dikkate alınırken, PEC ve PMC yüzeylerde hem gelen hem de yansıyan dalgalar hesaba katılmıştır. Farklı açıklık yarıçapları ve gözlem mesafeleri için toplam alanın uzaysal dağılımı grafiksel olarak karşılaştırılmış, yüzey tiplerinin alan üzerindeki etkileri ayrıntılı biçimde analiz edilmiştir. Sonuçlar, toplam alanın genlik ve faz karakteristiğinin yüzey tipine bağlı olarak belirgin biçimde değiştiğini göstermekte; özellikle PEC yüzeylerde yüksek frekanslı girişim desenleri, opak yüzeylerde ise daha düşük genlikli ve düzgün bir dağılım gözlenmektedir. Elde edilen bulgular, yüzey özelliklerinin toplam alan davranışı üzerindeki rolünü hem nitel hem de nicel olarak ortaya koymakta; anten tasarımı, elektromanyetik kalkanlama ve radar kesit alanı (RCS) azaltımı gibi mühendislik uygulamalarında yüzey seçimi ve optimizasyonu için yol gösterici bir referans sunmaktadır.
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    Evaluation of uniform diffraction behavior from circular apertures on opaque and perfectly conductive surfaces using BDW theories
    (Emerald, 2026-02) Altınel, Mustafa; Yalçın, Uğur; 414019
    This study presents a unified and comparative analysis of uniform diffraction fields generated by circular apertures on three canonical surface types: opaque, perfectly electric conductive (PEC) and perfectly magnetic conductive (PMC). This study aims to explore how these boundaries influence field uniformity and angular behavior under identical conditions.Design/methodology/approachThe classical boundary diffraction wave (BDW) theory is applied to the opaque case, and an extended BDW formulation is developed for PEC and PMC surfaces to account for reflective effects. Analytical expressions are derived, and numerical simulations are conducted to examine the impact of aperture size and observation distance.FindingsThe results reveal that PEC and PMC surfaces introduce significant modifications to the angular distribution of the diffracted field, including phase reversals and amplitude oscillations. The extended BDW model successfully predicts these behaviors, particularly near shadow boundaries and axial zones.Research limitations/implicationsThe study is limited to idealized geometries and monochromatic wave excitation. It does not yet consider material losses or complex aperture shapes. Future work may expand this framework to more realistic electromagnetic structures.Practical implicationsThe findings can help electromagnetic engineers optimize antenna design, stealth surfaces and metastructures by offering better control over field uniformity and diffraction behavior across different surface types.Social implicationsWhile the work is theoretical, it supports technological development in sectors like communication, defense and sensing, contributing indirectly to infrastructure reliability and performance.Originality/valueTo the best of the authors' knowledge, this is the first unified parametric study that simultaneously evaluates opaque, PEC and PMC surfaces using classical and extended BDW approaches. It introduces a novel high-frequency framework for comparing uniform diffraction field behavior across distinct boundary conditions.