Equivalent Circuit Analysis of Frequency Selection Surface Based on Transition Matrix Method

In this paper, the equivalent circuit analysis of frequency selection surface (FSS) based on transition matrix method is proposed. The equivalent circuit topology of FSS can be obtained by the electric field distribution, and the mapping relationship between equivalent circuit parameters and 3D structure parameters can be setup. Firstly, a full-wave simulation by HFSS (High Frequency Structure Simulator) and curve-fitting by MWO (Microwave Office) with different structure parameters of FSS is conducted, and a discrete database including the 3D structure parameters and the equivalent circuit parameters can be obtained. Then, a transition matrix relationship is established to map the relationship between 3D structure parameters and the equivalent circuit parameters. The objective function can be constructed and the least square method is used to complete the space mapping, each value in the transition matrix is a continuous function. Finally, a software is developed to verify this method, which can calculate the S parameters of more than ten types of single-layer FSS at different incident angles, permittivity and thickness.