Analysis of ring and rectangular slot FSS using a new equivalent circuit method

A new method which uses the spatial modal decomposition of the single FSS element has been applied for the analysis of a thin frequency selective structure (FSS) composed of rectangular slot elements. The method is based on the equivalent circuit approach and has exhibited more accurate results compared with conventional equivalent circuit approaches. In addition the method performs much faster compared to rigorous solutions. A good agreement in comparison with other methods and measurements has been revealed for several kinds of thin FSS.