Tham khảo tài liệu 'electromagnetic waves propagation in complex matter part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | High Frequency Techniques the Physical Optics Approximation and the Modified Equivalent Current Approximation MECA 227 the observation points analytically the incident wave is supposed to be a plane wave which impinges on the surface and generates a current density distribution with constant amplitude and linear phase variation. Assuming a flat triangular facet the radiation integral can be solved by parts. The good behaviour was proven in the validation examples where the results from the frequency sweep in the high frequency region agreed the theoretical values. Likewise an excellent overlapping was obtained for different angles of incidence when dealing with a non-PEC electrically large surface. Because one of the constraints to employ PO and MECA is the determination of line of sight between the source and the observation points some algorithms to solve the visibility problem were described. The classic methods are complemented by acceleration techniques and then they are translated into the GPU programming languages. The Pyramid method was explained as an example of fast algorithm which was specifically developed for evaluating the occlusion by flat facets. Undoubtedly this can be employed in joint with the MECA formulation but the Pyramid method can also be helpful in other disciplines of engineering. Throughout the section Application examples the way MECA becomes a powerful and efficient method to tackle different scattering problems for electrically large scenarios was satisfactorily demonstrated by means of the example consisting in the evaluation of the radio electric coverage in a rural environment. In addition to this other fields of application were suggested from the RCS computation to imaging techniques covering a wide range of electromagnetic problems. 7. References Arias . Rubinos . Cuinas I. Pino . 2000 . Electromagnetic Scattering of Reflector Antennas by Fast Physical Optics Algorithms Recent Res. Devel. Magnetics Vol. 1 No. 1 pp. .