Dual-polarization transmit-receive reflectarray antenna made of cells with two orthogonal sets of coplanar parallel dipoles

A dual-polarization dual frequency focused beam reflectarray antenna is designed for transmit-receive (Tx-Rx) operation in Ku Band. A novel broadband reflectarray element is introduced, which consists of two orthogonal sets of three parallel dipoles. To adjust the dimensions of the elements in the antenna, we have used the local periodicity assumption, and we have analyzed a multilayered periodic structure surrounding each element by means of a home-made software based on the method of moments in the spectral domain. This strategy makes it possible to design reflectarray antennas within reasonable CPU times. The designed antenna shows a bandwidth of 10.9% in Tx-band and 7.1% in Rx-band for gain variations lower than 1 dB. Also, levels of cross-polar components 30 dB below the radiation maximum have been achieved. In order to improve the crosspolar discrimination, the elements of the designed reflectarray have been slightly rotated, and this has made it possible to achieve levels of cross-polar components 35 dB below the maximum in both the Tx and the Rx band