Fast physical optics for smooth surfaces

A technique to compute the physical optics (PO) integral is presented. This technique is based on a decomposition of the surface in small triangles and a fast evaluation of each triangle by means of a deformation of the integration path in the complex plane. This algorithm permits a fast and accurate evaluation of the PO integral for smooth large surfaces. The technique consist of a blind code that computes the different contributions (stationary phase points, end points, etc.) numerically. The CPU time is almost independent with frequency.