A simple method to realize polarization diversity in broadband reflectarrays using single-layered rectangular patch elements

This paper presents a simple approach to achieve polarization diversity in broadband reflectarrays. The wideband characteristic of the reflectarray is realized by using rectangular patch elements arranged in a sub-wavelength grid on a single layer of substrate; while the polarization diversity of the reflectarray is achieved by simply rotating the feed horn antenna. Since the two orthogonal x- and y- component of the rectangular patch element exhibit relatively negligible interaction, the circular polarized (CP) reflectarrays with linearly polarized (LP) feed that have been proposed previously are found to be able to support quadruple polarizations, namely vertical polarization (VP), horizontal polarization (HP), right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP), by means of rotating the feed. The viability and effectiveness of the proposed simple approach for polarization diversity is experimentally confirmed. The measured results demonstrate that the 1-dB gain bandwidth for all four polarizations can reach as large as 18%. Moreover, the 3-dB axial ratio bandwidths for CP operations are considerably wide, above 36% and 40% for CP operations are considerably wide, above 36% and 40% for RHCP and LHCP, respectively.