An apparatus comprising: a phased array antenna for transmitting/receiving beamformed signals on a plurality of beams using a common frequency- and time-limited physical channel resource; said phased array antenna comprising: an array of antenna cells for electromagnetic radiation, wherein the antenna cells comprise: an antenna element; a first coupling structure at a first side of the antenna element for manipulating coupling with an adjacent antenna cell at a first side of the antenna element; a second coupling structure at a second side of the antenna element opposite to the first side for manipulating coupling with another adjacent antenna cell at the second side of the antenna element; a coupling factor of the first coupling structure differing from a coupling factor of the second coupling structure; wherein adjacent antenna cells of the array of antenna cells are mirror-symmetric structures.