Inter Coupling Modes Determination in Double Screen Frequency Selective Surfaces using the WCIP Method for Optimized Strip Length by Applying Real Genetic Algorithm

Abstract

This paper presents a novel approach based on optimizing the strip length of a Frequency Selective Surface (FSS) structure using a Real Genetic Algorithm (RAG) in conjunction with the Wave Concept Iterative Method (WCIP). Mean Squared Error (MSE) is used as an objective function to calculate the error between the desired resonant frequency and the estimated one obtained through WCIP for each individual within the population. The approach was validated on two strip FSS structures, FSS1 and FSS2, showing a remarkable accuracy with relative errors of 0.0033% and 0.0029%, respectively. The results were obtained using MATLAB. After optimizing the length strips of both FSSs and cascading them, a strategy for identifying the coupling modes between the resulting double-screen FSS structure is introduced. The extracted coupling modes indicate that increasing the separation distance between the two FSSs reduces the number of modes participating in the coupling between FSS1 and FSS2. Two inter-FSS distance tests were used to validate the inter-FSS coupling modes determination strategy, and a good agreement was recorded between all mode WCIP results and the limited coupling mode WCIP results.