Cross-polar reduction in reflectarray antennas by means of element rotation

A cross-polar reduction technique for dual-polarization reflectarray antennas is proposed. This technique is based on the determination of the rotation angle of each reflectarray element that minimizes the cross-polar components of the electric and magnetic fields reflected by that particular element in each polarization under local periodicity assumption. The results obtained with the cross-polar reduction technique have been validated by comparison with results provided by the commercial software CST®. The technique has been applied to the reduction of the cross-polarization radiated by a dual-polarization transmit-receive reflectarray antenna. The results obtained after cross-polar reduction show minimum values of cross-polar discrimination of 35 dB for one polarization and 40 dB for the orthogonal polarization, both in the Tx and Rx-bands.