Wideband 3-D-Printed Metal-only Reflectarray for Controlling Orthogonal
Linear Polarizations
Abstract
This paper 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°. 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 below 1.5 dB from 32 GHz 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 dBi to 30.3 dBi where the achieved
radiation efficiency is greater than 97%