Radyo Dalgası Yayılımı Modellemesi İçin Çoklu Engel Kırınım Yöntemlerinin Geliştirilmesi ve Karşılaştırmalı Analizi
Türköne, Nuriye Dicle
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Diffraction loss is defined as power dissipation in electromagnetic wave, which is originated through edges located near the propagation path between two fixed antennas. It is required to minimize the diffraction loss in a proper communication system in order to be able to transmit the information to the receiver without any problem. For this purpose, the number of edges that cause diffraction loss is determined and the structures of the edges are modelled. While a reliable communication system is designed, it is important to analyze the loss originating from diffraction in the communication system. In this study, the basic principles of diffraction loss calculations are explained. Several methods for diffraction loss calculations are examined for a single edge modelled as a knife-edge. In the case of multiple edges in a terrain profile, the Vogler method, which predicts the loss of diffraction by means of an analytical method, is introduced and developed in MATLAB. Epstein-Peterson, Deygout and Giovanelli methods, which predict the diffraction loss by using the geometrical parameters of knife-edges, are introduced and developed in MATLAB. Recursive algorithms are used for the simulation of iv Vogler, Deygout and Giovanell methods. The MATLAB programs developed for all methods are able to calculate diffraction loss for various types and numbers of edges. A performance assessment is conducted through comparing the results of all methods with those in the literature. The accuracy of Epstein-Peterson, Deygout, and Giovanelli methods is compared with respect to the Vogler method that is an analytical method. By using these methods, the diffraction loss which occurs when the edges are modelled as rounded peaks (knobs) with a certain radius, is also examined.