Problem-matched basis functions for moment method analysis - An application to reflection gratings

In the evaluation of the frequency response of a scattering object by the i ntegral equation technique, generally a large linear system of equations ha s to be solved for each frequency point, This paper deals with a technique that drastically reduces the size of the linear system without loss of accu racy. The key point is the definition of a set of problem-matched basis fun ctions. These basis functions are extremely efficient in the representation of the unknown in the parameter range of interest. In this way, the centra l processing unit (CPU) time required in the response evaluation is drastic ally reduced. Examples of application concerning reflection gratings are re ported.