An antenna system for providing identification functionality for an interrogating unit to identify a receving unit, wherein the antenna system is configured to be connected to a signal processing device of the interrogating unit, and wherein the antenna system comprises: • a main antenna, configured to at least transmit electromagnetic waves, and • an auxiliary antenna, configured to at least transmit electromagnetic waves, • a first channel interface arranged to be in connection to the main antenna by means of a first main antenna distribution network, configured to at least receive an electromagnetic waveform provided from the signal processing device when the antenna system is transmitting a sum channel interrogation signal via a first transmission channel being a sum transmission channel, and • a second channel interface arranged to be connectable to the main antenna by means of a second main antenna distribution network, configured to at least receive an electromagnetic waveform provided from the signal processing device when the antenna system is transmitting a delta channel interrogation signal via a second transmission channel being a delta transmission channel, the antenna system further comprises: a first switch and a transmission input means, wherein the first switch is configured to be capable to switch between a first operation mode of the first switch and a second operation mode of the first switch, wherein when the first switch is set in the first operation mode the second channel interface is set to be in connection with the auxiliary antenna, and wherein when the first switch is set in the second operation mode the second channel interface is set to be in connection with the main antenna, and wherein the transmission input means is configured to provide information to the first switch at least concerning if transmission via the first transmission channel is expected, wherein if transmission via the first transmission channel is expected the transmission input means is configured to set the first switch in the first operation mode, wherein when the first switch is operating in the first operation mode, if both transmission via the first channel interface and the second channel interface is executed, the signal provided via the first channel interface will be sent by the main antenna and the signal provided via the second channel interfacewill be sent by the auxiliary antenna. • a main antenna, configured to at least transmit electromagnetic waves, and • an auxiliary antenna, configured to at least transmit electromagnetic waves, • a first channel interface arranged to be in connection to the main antenna by means of a first main antenna distribution network, configured to at least receive an electromagnetic waveform provided from the signal processing device when the antenna system is transmitting a sum channel interrogation signal via a first transmission channel being a sum transmission channel, and • a second channel interface arranged to be connectable to the main antenna by means of a second main antenna distribution network, configured to at least receive an electromagnetic waveform provided from the signal processing device when the antenna system is transmitting a delta channel interrogation signal via a second transmission channel being a delta transmission channel, a first switch and a transmission input means, wherein the first switch is configured to be capable to switch between a first operation mode of the first switch and a second operation mode of the first switch, wherein when the first switch is set in the first operation mode the second channel interface is set to be in connection with the auxiliary antenna, and wherein when the first switch is set in the second operation mode the second channel interface is set to be in connection with the main antenna, and wherein the transmission input means is configured to provide information to the first switch at least concerning if transmission via the first transmission channel is expected, wherein if transmission via the first transmission channel is expected the transmission input means is configured to set the first switch in the first operation mode, wherein when the first switch is operating in the first operation mode, if both transmission via the first channel interface and the second channel interface is executed, the signal provided via the first channel interface will be sent by the main antenna and the signal provided via the second channel interfacewill be sent by the auxiliary antenna.