Beam-tracing-based inverse scattering for general aperture antennas

Iterative techniques are presented for two-dimensional inverse scattering from electrically large regions. The region is illuminated by transmitters with arbitrary profiles; this is an escalation in complexity from the line-source and the plane-wave excitations considered in many previous inverse-scattering studies. Imaging algorithms require an accurate and efficient forward model. Here a Gaussian-beam algorithm is utilized as a forward solver and is incorporated into an iterative-Born inversion scheme. General antenna profiles are incorporated into the algorithm by use of the matched-pursuits technique, by which the aperture fields are matched to the beam-tracing algorithm. Results are presented for several cases in which the simple Born approximation fails. Issues addressed include the types of profiles that can be successfully imaged, suitable antenna distributions, and the range of parameters over which the scheme is effective. Performance of the algorithm in the presence of noisy data is also tested.