A hierarchical aperture decomposition approach to fast analysis of lens and reflector antennas

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 and also to radomes. The multilevel computational sequence is based on hierarchical decomposition of the aperture and comprises two main steps. First, computation of the radiation patterns of all subdomains of the finest level over a very coarse angular grid. Second, multilevel aggregation of the radiation patterns of neighboring subdomains into the final pattern of the whole aperture via phase compensated interpolation. The multilevel algorithm attains computational complexity comparable to that of the FFT while avoiding its limitations.