Design of Linear-to-Circular Polarization Transformers Made of Long Densely Packed Metallic Helices

TL;DR

This paper introduces a new homogenization model for long metallic helices to design polarization transformers that efficiently convert linear to circular polarization with high transmission efficiency.

Contribution

A novel homogenization approach for long metallic helices enabling the design of efficient linear-to-circular polarization transformers.

Findings

Transmission efficiency up to 95%

Effective medium parameters derived analytically

Full wave simulations support theoretical predictions

Abstract

In this work, we study the realization of realistic polarization transformers formed by long metallic helices. To this end, we propose a new homogenization model to characterize the propagation of electromagnetic waves in medium formed by infinitely long helices. We derive approximate analytical expressions for the effective permittivity, effective permeability and the magnetoelectric tensor of the composite material, taking into account the effects of spatial dispersion. We apply the new homogenization model to characterize novel linear-to-circular polarization transformers. Our results show that the metamaterial screen may be designed in such a way that an incoming linearly polarized wave may be transformed into a circularly polarized transmitted wave, and that the transmission efficiency of such polarization transformer may be as high as 95%. The theoretical results are supported by full wave simulations.