An antenna arrangement for a Multiple Input Multiple Output (MIMO) radio system, the antenna arrangement transmitting and receiving in three essentially uncorrelated polarizations. The arrangement includes three parallel, stacked patches separated by first and second slots. A first feeding line feeds the first patch, and at least a second and third feeding line feed the second patch. In a first operating mode, the first feeding line generates a first constant E-field in the first slot between the edges of the first and second patches. In a second operating mode, the second feeding line contributes to a second, sinusoidally varying E-field in the second slot between the edges of the second and third patches. In a third operating mode, the third feeding line contributes to a third, sinusoidally varying E-field in the second slot between the edges of the second and third patches.