Multilevel fast physical optics algorithm for radiation from non-planar apertures

A novel multilevel algorithm for computing the radiation patterns of nonplanar aperture antennas over a range of observation angles is presented. The proposed technique is directly applicable to reflector and lens antennas as well as to radomes. The multilevel computational sequence is based on a hierarchical decomposition of the radiating aperture and comprises two main steps. First, computation of the radiation patterns of all subapertures of the finest level over a very coarse angular grid. Second, multilevel aggregation of the radiation patterns of neighboring subapertures into the final pattern of the whole aperture via a phase compensated interpolation. The multilevel algorithm attains computational complexity comparable to that of the fast Fourier transform based techniques while avoiding their limitations.