Antenna arrangement and method for beamforming

1. A user equipment (UE), the UE comprising:

an antenna arrangement comprising:

an antenna array comprising: a first set of at least two antenna elements and a second set of at least two antenna elements, wherein i) each antenna element included in the first set of antenna elements has a first polarization (P 1 ) and ii) each antenna element included in the second set of antenna elements has a second polarization (P 2 ) that is different than the first polarization (P 1 ); and

a reconfigurable feed network connected to the antenna array, wherein

the reconfigurable feed network comprises a switching network comprising one or more physical switches for switching the reconfigurable feed network between:

A) a first mode providing single polarization beamforming (SPBF), in which first mode the physical switches of the reconfigurable feed network: i) connects to a first port (Port-A) each antenna element included in the first set of antenna elements and ii) connects to a second port (Port-B), which is separate from the first port (Port-A), each antenna element included in the second set of antenna elements, wherein, in the first mode, no antenna element having the second polarization is connected to Port-A and no antenna element having the first polarization is connected to Port-B, and

B) a second mode providing dual-polarization beamforming (DPBF), in which second mode the physical switches of the reconfigurable feed network: i) connects to the first port (Port-A) both: 1) a first subset of the first set of antenna elements and 2) a first subset of the second set of antenna elements such that at least one antenna element having the first polarization (P 1 ) is connected to Port-A and at least one antenna element having the second polarization (P 2 ) is also connected to Port-A and ii) connects to the second port (Port-B) both: 1) a second subset of the first set of antenna elements and 2) a second subset of the second set of antenna elements such that at least one antenna element having the first polarization (P 1 ) is connected to Port-B and at least one antenna element having the second polarization (P 2 ) is also connected to Port-B, and

each recited subset of antenna elements comprises at least one antenna element, and further wherein

the UE is not a base station or a component of a base station.

2. The UE of claim 1 , wherein, in the second mode, the antenna elements of the antenna array are functionally arranged into a first and a second antenna array and wherein each of the first antenna array and of the second antenna array are arranged along a dimension for which the beam shall be broadened.

3. The UE of claim 1 , arranged to be switched to the first mode upon a transmission requiring a narrow beam.

4. The UE of claim 1 , arranged to be switched to the second mode upon a transmission requiring a wide beam.

5. The UE of claim 1 , wherein

half of the antenna elements from the first set of antenna elements are included in the first subset of the first set of antenna elements, and

half of the antenna elements from the second set of antenna elements are included in the first subset of the second set of antenna elements.

6. A method for beamforming performed by user equipment (UE) using an antenna arrangement comprising a dual polarized antenna array and a reconfigurable feed network connected thereto, the dual polarized antenna array comprising a number of radiating antenna elements, the method comprising:

switching the feed network to a first mode providing single polarization beamforming (SPBF), in which first mode the feed network is arranged such as to connect all antenna elements having a first polarization P 1 to a first port, A, and all antenna elements having a second polarization P 2 to a second port, B; and

switching the feed network to a second mode providing dual-polarization beamforming (DPBF), in which second mode the feed network connects a part of all antenna elements having a first polarization P 1 and a part of all antenna elements having a second polarization P 2 to the first port, A, and a remaining part of all antenna elements having the first polarization P 1 and a remaining part of all antenna elements having the second polarization P 2 to the second port, B, wherein

the UE is not a base station or a component of a base station.

7. The method as claimed in claim 6 , wherein, in the second mode, the antenna elements of the antenna array are functionally arranged into a first and a second antenna array and wherein each of the first antenna array and of the second antenna array are arranged along a dimension for which the beam shall be broadened.

8. The method as claimed in claim 6 , further comprising switching to the first mode upon a transmission requiring a narrow beam.

9. The method as claimed in claim 6 , further comprising switching to the second mode upon a transmission requiring a wide beam.

10. The method as claimed in claim 6 , wherein

one half of all of the antenna elements having the first polarization P 1 are connected to the first port; and

one half of all of the antenna elements having the second polarization P 2 are connected to the first port.

11. The method as claimed in claim 6 , wherein the UE is a mobile phone.

12. A computer program product comprising a non-transitory computer readable medium storing a computer program for a user equipment (UE), the computer program comprising computer program code, which, when run on processing circuitry of the UE causes the UE to perform the method of claim 6 .

13. The UE of claim 1 , wherein the one or more physical switches comprise one or more electronic switches.

14. The UE of claim 1 , wherein the one or more physical switches comprise one or more mechanical switches.