İki kırınım içeren senaryolar için kapsama alanı haritalaması
Küçük Resim Yok
Tarih
2018
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Bursa Teknik Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu tezde, 2 boyutlu bıçak kenarlı yapılardan oluşan çeşitli senaryolar için kullanılan ışın izleme tabanlı nümerik elektromanyetik modelleri özetlendi. Geometrik Optik (GO) ve Düzgün Kırınım Teorisi (DKT) metodları detaylıca incelendi. Asimptotik metotların avantaj ve dezavantajları, tam dalga metotlarla kıyasla üstün olduğu ve zayıf olduğu noktalar ve kullanılabileceği ve kullanılamayacağı özel durumlar açıklandı. Elektromanyetizma fenomenini açıklayan Maxwell denklemlerinin yüksek frekans açılımı yapılarak ışın tabanlı asimptotik metotların teorik temelleri incelendi. İki boyutlu çizgisel segmentler kullanılarak oluşturulan çeşitli yayılım senaryolarında ışın yollarını hesaplayabilen ışın izleme algoritması geliştirildi. Elde edilen ışın yolları Geometrik Optik ve Düzgün Kırınım Teorisi denklemleri içerisinde kullanıldı, alıcıya hiç bir engel ile karşılaşmadan doğrudan varan ışınlar, yansıyarak varan ışınlar ve bunların ikili kırınıma kadar olan kombinasyonları hesaba katılarak tüm bir yayılım ortamındaki elektromanyetik alanın hesabı yapıldı. Elektrik alan şiddetinin engel arkasında kırınıma bağlı olarak oluşan maksimumları bulundu ve bağlı olduğu değişkenler ortaya konuldu. Bilgisayar ortamında geliştirilen Işın izleme, Geometrik Optik ve Düzgün Kırınım Teorisi algoritmalarının, toplam çözüm süresine olan etkileri incelendi. Geliştirilen kod paralel çözüme uygun hale getirilerek, çözüm süresi düşürüldü. GO-DKT algoritmasının paralel performansı ortaya konuldu. Geliştirilen yazılımla, elektromanyetik uyumluluk ve anten yerleştirme gibi farklı elektromanyetik problemler için çözümler elde edildi. Işın izleme tabanlı GO-DKT modelinin verimliliği ve sonuçların doğruluğu FEKO yazılımındam elde edilen sonuçlarla kıyaslanarak tartışıldı ve doğrulandı. Seçilen bir kırsal yayılım senaryosunda vericinin konumunun elektromanyetik alan ve kapsama alanı üzerine etkisini gözlemelemek amacıyla çeşitli simülasyonlar tekrarlandı ve verici anten konumunun değişiminin sebep olduğu sonuçlar tartışıldı.
In this thesis, numerical electromagnetic models, which is used for 2-dimensional propagation scenarios including knife-edge structures are studied and explained. Geometrical Optics and Uniform Theory of Diffraction models are analysed in detail. The points where asymptotic methods are superior to and weaker than full wave methods and special cases that can be used and exploited are explained. Maxwell's equations which explain the phenomenon of electromagnetism have been investigated by high-frequency expansions and the theoretical basis of ray optic asymptotic methods were showed. A ray tracing algorithm that can work for rural and urban propagation environments which are created using two-dimensional linear lines has been developed. The obtained ray paths were used in the equations of Geometric Optics and Uniform Theory of Diffraction. Coverage area simulation is made by using all type of possible rays which are direct rays, reflected rays, diffracted rays and combination of all these types of rays. the maximums of the electric field generated due to the diffraction behind the obstacle were found and the diffraction effects on the electric field behind the obstacle were investigated. The effects of ray tracing, geometric optics and uniform diffraction theory algorithms on the total solution time were investigated. Improved parallelization of the code has reduced the solution time. The parallel performance of the GO-UTD algorithm has been demonstrated. With the developed software, solutions were obtained for different electromagnetic problems such as electromagnetic compatibility and antenna placement. The efficiency of the ray tracing based GO-UTD model and the accuracy of the results were discussed in comparison with the results obtained from FEKO software. In a selected rural propagation scenario, various simulations were repeated in order to observe the influence of the transmitter position on the electromagnetic field and the coverage area, and the variations that caused by the change of the transmitter antenna position was discussed.
In this thesis, numerical electromagnetic models, which is used for 2-dimensional propagation scenarios including knife-edge structures are studied and explained. Geometrical Optics and Uniform Theory of Diffraction models are analysed in detail. The points where asymptotic methods are superior to and weaker than full wave methods and special cases that can be used and exploited are explained. Maxwell's equations which explain the phenomenon of electromagnetism have been investigated by high-frequency expansions and the theoretical basis of ray optic asymptotic methods were showed. A ray tracing algorithm that can work for rural and urban propagation environments which are created using two-dimensional linear lines has been developed. The obtained ray paths were used in the equations of Geometric Optics and Uniform Theory of Diffraction. Coverage area simulation is made by using all type of possible rays which are direct rays, reflected rays, diffracted rays and combination of all these types of rays. the maximums of the electric field generated due to the diffraction behind the obstacle were found and the diffraction effects on the electric field behind the obstacle were investigated. The effects of ray tracing, geometric optics and uniform diffraction theory algorithms on the total solution time were investigated. Improved parallelization of the code has reduced the solution time. The parallel performance of the GO-UTD algorithm has been demonstrated. With the developed software, solutions were obtained for different electromagnetic problems such as electromagnetic compatibility and antenna placement. The efficiency of the ray tracing based GO-UTD model and the accuracy of the results were discussed in comparison with the results obtained from FEKO software. In a selected rural propagation scenario, various simulations were repeated in order to observe the influence of the transmitter position on the electromagnetic field and the coverage area, and the variations that caused by the change of the transmitter antenna position was discussed.
Açıklama
Fen Bilimleri Enstitüsü, Elektrik-Elektronik Mühendisliği Ana Bilim Dalı
Anahtar Kelimeler
Elektrik ve Elektronik Mühendisliği, Electrical and Electronics Engineering
