Efficient analysis of FSS using the MoM-based Maehly approximation

The Rao-Wilton-Glisson (RWG) subdomain basis function is employed to represent the current distribution of arbitrary frequency selective surface (FSS) geometry in spectral domain method of moments (MOM). The best uniform rational approximation, performed by the Maehly approximation, is applied to obtain an accurate representation of the response over a broad bandwidth. The effectiveness of the presented method is evaluated by defining the relative root-mean-square (RMS) error of reflection. Three practical broad-band examples are given to compare with the exact results, including patch-type ring, rectangle and cross cells. Good agreement between the Maehly approximation and the exact solution is observed. Compared with traditional MoM and Chebyshev approximation, the proposed technique is more efficient with lower memory required.