Analysis of the electromagnetic scattering characteristics of large-aperture parabolic surface based on symmetrical timedomain near-field physical optics method

Radio telescopes are highly sensitive, and the interference signals reflected by the large aperture paraboloid have a significant influence on the observing system. Further, electromagnetic compatibility analysis of radio telescopes is a research problem that cannot be ignored. To address the issue of electric -large target in the near -field coupling analysis of the large -diameter paraboloid, a spatial symmetry -based time -domain near -field physical optics method is proposed herein. The principle of establishing the near -field electromagnetic scattering model of the paraboloid by physical optics approximation is described. The local Green's function approximation method was employed to simplify the calculation process, and the surface element integration was performed by the Gaussian numerical integration method. On this basis, combined with paraboloid structure and application scenarios, an efficient spatial symmetry -based calculation method is proposed. Finally, the accuracy and efficiency of the algorithm were evaluated based on a rectangular metal plate and a small -aperture parabolic, and the near -field scattering characteristics of the large -diameter (25 m) paraboloid antenna were analyzed. The proposed symmetric time -domain near -field physical optics method offers a technical approach for the near -field coupling analysis of large radio telescopes.