Diffraction Loss Estimation on Rounded Obstacles by the Logarithmic - Cell - Simulation Method

Radio-wave propagation distances to 100…200km are the most important for EMC now. Diffraction factor is dominant on these distances. The paper proposes the development of heuristic Logarithmic -Cell - Simulation computer method for some rounded obstacles diffraction loss estimation on such distances (Logarithmic -Cell -Simulation method is described in title “Multiple -Knife - Edge Diffraction Loss Estimation by the Logarithmic -Cell -Simulation Method”, 15th Wroclaw EMC Symposium Trans., 2000). Simulation is carried out on cell working space. Working space is two-dimensional: “distance-height”. Scale of dimensions is logarithmic. Condition of cell can be change accordance to some rules. Development of changing process simulates radio-wave propagation. We can simulate obstacles (knife or rounded) on the propagation path. Round shape of obstacle we can take into account in formation of path model. Time of “propagation” defines the propagation loss. We can compare the results of this method with results of real propagation path diffraction losses and with results of analytic calculations. Results show us a good accordance with ITU-R Recommendation 526 and experiment.