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 integral equation technique, generally a large linear system of equations has 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 accuracy. The key point is the definition of a set of problem-matched basis functions. These basis functions are extremely efficient in the representation of the unknown in the parameter range of interest. In this way, the central processing unit (CPU) time required in the response evaluation is drastically reduced. Examples of application concerning reflection gratings are reported.