Multilevel Physical Optics Algorithm Research Articles

Multilevel Physical Optics Algorithm for Near-Field Double-Bounce Scattering

A fast algorithm for the evaluation of the double-bounce (DB) contributions to the physical optics scattering integrals, over a range of aspect angles and frequencies, is presented. The work extends the preceding far-field algorithm, to encompass three-dimensional and near-field scenarios. The algorithm relies on multilevel sampling and interpolation of phase- and amplitude-compensated contributions of subdomain pairs. A particular design of the phase- and amplitude-compensation functions and sampling grids, tailored to the DB near-field case, is presented. The improved performance and error controllability are demonstrated via representative examples.

Multilevel Physical Optics Algorithm for Near Field Scattering

An algorithm for the fast computation of the physical optics (PO) integral describing single bounce back scattering in near-field scenarios is presented. The algorithm is based on a multilevel computation of partial contributions to the PO integral by hierarchically ordered subdomains. Phase- and amplitude-compensation of the partial contributions allows for their coarse sampling over non-uniform spherical grids. The solution is obtained by gradual aggregation of such partial contributions via interpolation on progressively denser grids. The computational complexity is further reduced by representation of small subdomains' contributions via their far-field patterns and transition to the near-field representations only at a higher level. Speed-up, accuracy, and error controllability are demonstrated.

Improved multilevel physical optics algorithm for fast computation of monostatic radar cross section

This paper proposes an acceleration technique to fast evaluate the monostatic radar cross section (RCS) with the multilevel physical optics (MLPO) algorithm. The proposed method combines the adaptive cross approximation (ACA) algorithm with the MLPO to fast evaluate two-dimensional monostatic RCS (two-dimensional monostatic RCS over a range of elevation angles θ and azimuths angles φ at a fixed frequency f, or a range of frequencies f and azimuths angles φ at a fixed elevation angle θ) responses. Owing to the phase compensation in the MLPO, the matrix corresponding to the compensated back-scattered field of each group is highly rank-deficient, which is compressed with ACA in a multilevel fashion therefore a lot of central processing unit time will be saved. The rank-deficiency, accuracy and computational complexity of the proposed method have been studied through a couple of numerical examples, which illustrate the effectiveness of the proposed approach.

Generalized Multilevel Physical Optics (MLPO) for Comprehensive Analysis of Reflector Antennas

Recent developments of the multilevel physical optics (MLPO) algorithm aiming at the comprehensive analysis of complex reflector antenna systems are presented. The physical theory of diffraction (PTD) line integral along the rim of a reflector is combined with the physical optics (PO) surface integral within the multilevel algorithm. The multilevel scheme is also generalized to combine fields radiated by various components of different sizes, as encountered in complex antenna systems with multiple feeds and/or reflectors. Comparison with published results demonstrates the ability of the MLPO algorithm to cope accurately and efficiently with realistic reflector antenna problems.

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

Abstract 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.