Prediction Of Electromagnetic Wave Propagation Characteristics Based On Ray Tracing Algorithm

In recent years, the prediction of electromagnetic wave propagation characteristics in various environments has made an important role in wireless communication system planning. The ray tracing method is a widely used for prediction of the radio propagation characteristics. The method is developed from the geometrical optics, geometrical theory of diffraction, and uniform theory of diffraction.In this thesis, an imporved tree-dimensional simplex ray tracing algorithm is proposed. Key techniques of the algorithm are studied. The contributions of this thesis are as follows:(1) The tree-dimensional simplex fast ray tracing algorithm is based on space division. In this algorithm, the space of the electromagnetic wave propagation is divided into a number of discrete tetrahedrons. In the space, the ray path is determined by the geometry relations of the tetrahedrons and the facet features of the interfaces between the tetrahedrons. Compared with other ray tracing algorithm, the simplex ray tracing does not need to intersection test. Therefore, our algorithm has a higher efficiency. Two improved methods of finding the tetrahedral geometry relation and obtaining the facet features of tetrahedrons are presented.(2) The directivities and polarizations of the antennas of the transmitter and receiver are considered so that the simplex ray tracing algorithm can be applied to a variety of different radiational sources. In addition, the method of the fast ray tracing in a complex environment is also researched.(3) The method of finding the tetrahedral geometry relation, obtaining the facet features of tetrahedrons, ray tracing, ray reception, and field strength calculation are implemented in Fortran. The extraction of output data that generated by modeling software such as GMSH is implemented in Python, and then they are integrated in a Python script by using f2 py which is a hybrid programming tool. At last, some models are created to predict the path-loss and the electric field using our algorithm. The results of program are compared with the results of other literatures and measurements.