Wideband 3-D-Printed Metal-Only Reflectarray for Controlling Orthogonal Linear Polarizations

This article presents a metal-only reflectarray that enables the control of incident orthogonal polarizations in a large bandwidth. The proposed reflectarray is based on a unit cell whose tuning elements allow the independent control of the reflection phase value for the vertical and horizontal impinging polarizations. Due to the symmetry of the unit cell, the same performance is produced by each polarization when its reflection phase response is modified. The proposed unit cell provides a fairly linear phase response along the frequency with a phase variation in the orthogonal polarization of +/- 1 degrees. The performance under oblique incidence and the frequency limitation of the unit cell are also investigated. From this unit cell, a metal-only reflectarray that produces circular polarization from a linear polarization is designed. The reflectarray presents a simulated directivity greater than 27 dBi with an axial ratio (AR) below 1.5 dB from 32 to 50 GHz (43.9% of bandwidth). A prototype is fabricated and the measured results agree well with the simulated ones. The obtained aperture efficiency is between 56% and 41% in the considered frequency band. The measured realized gain ranges from 27 to 30.3 dBi where the achieved radiation efficiency is greater than 97%.

Automated summary

This article presents a metal-only reflectarray that can control incident orthogonal polarizations in a large bandwidth. The proposed reflectarray is based on a unit cell that allows independent control of reflection phase for vertical and horizontal polarizations. The unit cell provides a fairly linear phase response and the reflectarray achieves great performance with a simulated directivity greater than 27 dBi and an axial ratio below 1.5 dB within a bandwidth of 32 to 50 GHz.