Analysis of the RATAN-600 radiotelescope antenna with a multilevel Physical Optics algorithm

The RATAN-600 antenna is a flexible multireflector system composed of reflectors of very large dimensions. An extended system, with improved performance in the millimetric range, includes a focal receiver array. Accurate electromagnetic analysis of such a system, and simulation of three-dimensional (3D) patterns, represents a substantial computational challenge. A fast Physical Optics method based on a multilevel subdivision of the surfaces of integration is proposed to address this problem. This method allows to perform Physical Optics integrals with a computational complexity comparable to that of the Fast Fourier Transform. The algorithm and initial numerical results of its application to the RATAN-600 antenna system are presented.