<p>A broadband dual-polarized single-layer
1-bit unit cell is proposed for achieving the independently controllable
dual-beam reflectarray antenna. The unit cell independently provides two-state
phase compensation for two orthogonally linearly-polarized waves. The
180-degree reflective phase difference between the two states is achieved by
tuning the magnetic resonance of State 0 and the electrical resonance of State
1. With its two resonances close to each other, the unit cell has a reflective
phase difference of 180±20 degrees
between two states over a broad bandwidth of 27.2-51.1 GHz. The
cross-polarization levels of below -30 dB ensure the high isolation between two
polarizations. Using the proposed dual-polarized unit cells, a 1-bit dual-beam
reflectarray antenna is designed and excited by a dual-polarized horn to show
the ability of independently controlling two orthogonally linearly-polarized
waves. At 33 GHz, the beams direct to -15 degrees and 20 degrees for the
feeding of horizontally and vertically polarized port, respectively. The 1.5-dB
gain bandwidth is greater than 20% for both polarizations. The proposed
dual-polarized reflectarray antenna with independently controllable 1-bit dual
beams provides an alternative design for the multiuser multiple-input
multiple-output applications.</p>
A Compact Single Layer Reflectarray Antenna Based on Circular Delay-Lines for X-band Applications
