Broadband Dual-Polarized Single-Layer Reflectarray Antenna with
Independently Controllable 1-Bit Dual Beams
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.