Numerical evaluation of antennas field using a new aperture-like expansion

The effectiveness of a new, aperture-like expansion for the evaluation of the field radiated by reflector antennas has been assessed and validated by a numerical investigation of the full, three-dimensional case. The method, which can be extended to near-field computations, is shown to retain the flexibility of standard physical optics techniques without incurring long computation times. These features are valuable in cases where the standard geometrical theory of diffraction cannot be applied, and for the evaluation of the near field of complex feeds as an alternative to spherical wave expansion.