ABSTRACT
A variety of numerical, asymptotic, and hybrid techniques are available for analyzing complex electromagnetic radiation, propagation, and scattering problems. Although numerical techniques such as the method of moments, finite difference time domain methods, finite element method, and others can be used to analyze complex geometrics, they become less efficient as the electrical size of the computational domain increases. All the solutions are applicable to perfect electric conducting surfaces that are used to model metallic conductors; however, there are many applications where the surfaces are not metallic conductors. One of the most commonly used methods for antenna pattern analysis, especially for reflector antennas, is the physical optics (PO) technique, known as the surface current method. PO is an high-frequency method that can be used to calculate the fields scattered from an electrically large object. To improve the accuracy of the PO fields, it is necessary to improve the accuracy of the currents, especially in the regions where diffracted effects are important.
