A dual polarity antenna including: a first radiator for radiating or for receiving a first radio-frequency (RF) wave having a first linear polarisation, and a second radiator for radiating or for receiving a second RF wave having a second linear polarisation orthogonal to the first linear polarisation. The first radiator includes one or more electrically conductive parts and the second radiator is provided by one or more slots in the one or more electrically conductive parts. An antenna column array may be densified and the size of the array columns may be reduced by locating and/or embedding the second radiator in the first radiator.