  A lesser-known but powerful application of parabolic equation methods is to
the target scattering problem. In this paper, we use noncanonically shaped
objects to establish the limits of applicability of the traditional approach,
and introduce wide-angle and multiple-scattering approaches to allow accurate
treatment of concave scatterers. The PE calculations are benchmarked against
finite-element results, with good agreement obtained for convex scatterers in
the traditional approach, and for concave scatterers with our modified
approach. We demonstrate that the PE-based method is significantly more
computationally efficient than the finite-element method at higher frequencies
where objects are several or more wavelengths long.
