Enhancement of Dual-Band Reflection-Mode Circular Polarizers Using Dual-Layer Rectangular Frequency Selective Surfaces

TL;DR

This paper introduces a dual-layer rectangular patch design for reflection-mode circular polarizers that significantly enhances bandwidth and view angle at two frequency bands, validated through simulation and measurements.

Contribution

It presents a novel dual-layer rectangular patch structure that improves bandwidth and view angle of dual-band reflection-mode circular polarizers over single-layer designs.

Findings

Bandwidths of 30.5% and 33.7% for less than 3 dB axial ratio at specified incident angles.

Significant improvement in view angle and bandwidth compared to single-layer RMCPs.

Simulation results are confirmed by measurements at multiple incident angles.

Abstract

A new kind of dual-band reflection-mode circular polarizers (RMCPs) is introduced with wide bandwidth and wide-view at the operating frequencies. The proposed RMCPs are based on dual-layer rectangular patches on both sides of a substrate, separated by a foam or air layer from the ground plane. Required TE susceptance of the first layer patches to produce circular polarization is calculated using the equivalent transmission line model. Dimensions of the RMCP are obtained using parametrical study for the two frequency bands, 1.9-2.3 GHz and 7.9-8.3 GHz. In addition, it is indicated that the accepted view angle and bandwidth of the proposed dual-layer RMCP are improved compared with the single layer RMCP, significantly. Moreover, a tradeoff is observed for the dual-layer RMCP on the bandwidths of X band and S band that can be controlled by propagation angle of the incident wave. The proposed RMCP has 30.5 % and 33.7 % bandwidths for less than 3 dB axial ratio with incident angles {\theta}max=50{\deg} and {\theta}min=35{\deg}. Finally, simulation results are met by the measurement for three angles of the incident wave.