Antenna system and a radio communication device including an antenna system

An antenna system including an antenna device and feed device for transmitting and receiving RF waves, comprising:

• a radiating structure having a first and a second end, said radiating structure including N helical radiating elements, being coextending and coaxially arranged on a support structure, where N is an integer greater than one,
• a feed portion for each respective helical radiating element provided at the first end of said radiating structure,
• a feeding means being connected, at N connections to each one of said feed portions of said helical radiating elements, said feeding means having connection means for connection to circuitry of a radio communication device, said feeding means including a phasing network for phasing the signals on said N connections, in order to provide for transmission/reception of circularly polarized RF waves in a first mode of operation, and
• means arranged for essentially uniform excitation of the helical radiating elements in order to provide for transmission/reception of linearly polarized RF waves in a second mode of operation.