An antenna module, in particular for a base station of a cellular mobile radio network, comprising a group of radiating elements capable of receiving and/or transmitting electromagnetic waves having at least two different, preferably linear orthogonal, polarizations, said antenna module further comprising at least one passive decoupling element. Said decoupling element extends with its longest dimension in a direction which is substantially perpendicular to a direction of propagation of said electromagnetic waves and/or substantially parallel to a ground plane and thus improves a degree of decoupling between said polarizations.