An improved equivalent circuit model for analysis of frequency selective surface based on MDECM

In order to accurately predict the frequency selective surface (FSS) characteristics in wide band, an improved equivalent circuit model for slot FSS is proposed. Based on modal decomposition equivalent circuit method (MDECM), higher-order waveguide modes have been taken into account for approximating the FSS element aperture field. Taking rectangular slot FSS as example, the ratio of the transformers is derivate. Numerical results are given to demonstrate good performance of the proposed method in wide band. The mutual coupling between higher-order waveguide modes for rectangular slot FSS has been investigated.