Dual polarization antenna array with very low cross polarization and low side lobes

An antenna array for radiation or reception of electromagnetic radiation, comprising:

• a plurality of antenna elements including at least one group of four adjacent linearly polarized antenna elements, the antenna elements having radiation patterns selected from a group consisting of a first, second, third and fourth radiation pattern,
• the first and second radiation patterns being different and being mirror images of one another with respect to a selected first plane of symmetry,
• the third and fourth radiation patterns being different mirror images of one another with respect to the selected first plane of symmetry,
• the first and fourth radiation patterns being different and being mirror images of one another with respect to a second selected plane of symmetry that is perpendicular to the first selected plane of symmetry, and
• the second and third radiation patterns being different and being mirror images of one another with respect to the second selected plane of symmetry,
• characterized in that either
• the antenna elements of the at least one group of four adjacent antenna elements have substantially identical radiation patterns two by two, respectively, and are positioned either
• in a substantially rectangular grid in such a way that the two antenna elements having substantially identical radiation patterns are positioned on opposite sides of a plane that is substantially perpendicular to the substantially rectangular grid and includes selected centers of each of the other two antenna elements of the group, or
• substantially along an axis in such a way that the two antenna elements positioned at innermost positions of the group have substantially identical radiation patterns and the two antenna elements positioned at outmost positions of the group have substantially identical radiation patterns, or
• the four radiation patterns of the antenna elements of the at least one group of four adjacent antenna elements are different from one another and the antenna elements are positioned substantially along an axis,
• whereby formation of grating lobes are inhibited in selected directions of the radiation and cross-polarization within the main lobe is suppressed at least 30 dB below the main lobe peak value.