Cross-polarization Control in FSSs by means of an Equivalent Circuit Approach

TL;DR

This paper introduces an efficient equivalent circuit approach for analyzing and designing frequency selective surfaces (FSS) with controlled polarization, enabling faster computation, physical insight, and integration with optimization and AI techniques.

Contribution

The paper presents a novel equivalent circuit method based on Floquet modal expansion for analyzing co- and cross-polarization in FSSs, facilitating rapid design and physical understanding.

Findings

Validated approach on various FSS configurations

Accurate prediction of cross-polarization components

Reduced computational effort compared to full-wave simulations

Abstract

This paper presents an efficient equivalent circuit approach (ECA), based on a Floquet modal expansion, for the study of the co- and cross-polarization in frequency selective surfaces (FSS) formed by periodic arrays of patches/apertures in either single or stacked configurations. The ECA makes it possible the derivation of analytical expressions for the generalized scattering parameters associated with the proposed circuit networks. Furthermore, the proposed circuit approach is an efficient surrogate model that can be combined with optimization techniques and artificial intelligence algorithms for the efficient design of FSS structures, saving efforts in the computation compared to time-consuming full-wave simulators and tedious synthesis (simulation-assisted) techniques. Due to the simplicity of the topology of the involved networks, the ECA can also be advantageously used to gain physical insight. The proposed approach is applied and validated in different FSS configurations where the cross-pol component plays a fundamental role in the design, as in circular polarizers, polarization rotators, and reflectarray cells.