An antenna array comprising at least two sets of antenna unit elements is disclosed. Each set of antenna unit elements supports a respective frequency band, wherein a vertical center-to-center distance between the antenna unit elements of a lowest frequency among the respective frequency bands is more than twice the vertical extension, D, of convex hull containing one antenna unit element of the lowest frequency, and antenna unit elements of at least a second set are arranged interleaved with the antenna unit elements of the lowest frequency. An arrangement comprising the antenna array and a network node is also disclosed.