A method for transmitting a signal using a beamforming antenna array, the method being performed by a network node, the method comprising: obtaining an indication for transmission of the signal requiring use of a partial antenna array Z of the antenna array X, the partial antenna array requiring less than all of the physical elements of the antenna array for transmission, wherein the antenna array is of size N x x M x dual polarized antenna elements, the partial antenna array is of size N z x M z dual polarized virtual antenna elements, and M and N are the dimensions of respective antenna array, the antenna array being regarded as a matrix X ∈ C 2N x x M x describing the excitation in the aperture of the antenna elements with polarization A and polarization B, the partial antenna array being regarded as a matrix Z ∈ C 2N z x M z; forming (S10 4) virtual antenna elements corresponding to the partial antenna array Z, thereby reducing the full antenna aperture of the antenna array X along the dimension M by means of a reduction matrix Q and then along the dimension N by means of a reduction matrix R, wherein Q ∈ C 2M x x 2 M z and R ∈ C 2N x x 2 N z, wherein the virtual antenna elements are formed by the reduction matrices Q and R being applied to all antenna elements of the antenna array X; expanding the partial antenna array including determining weight factors W p applied to the virtual antenna elements which connect the virtual antenna elements to a greater number of physical antenna elements than the partial antenna array such that the virtual antenna elements at least partly utilize the full antenna aperture, wherein expanding the partial antenna array comprises: i) determining (S106a) the weight factors for a weight matrix W v ∈ C 2N z x M z, where W v is obtained for the beam shape to be used for transmission of the signal; ii) expanding (S106b), using the reduction matrices Q and R, the weight matrix W v into a weight matrix W p ∈ C 2N x x M x such that the virtual antenna elements at least partly utilize the full antenna aperture; and iii) applying (S106c) the weight matrices to the virtual antenna elements; and initiating transmission of the signal using the array of the virtual antenna elements while applying the determined weight factors W p. obtaining an indication for transmission of the signal requiring use of a partial antenna array Z of the antenna array X, the partial antenna array requiring less than all of the physical elements of the antenna array for transmission, wherein the antenna array is of size N x x M x dual polarized antenna elements, the partial antenna array is of size N z x M z dual polarized virtual antenna elements, and M and N are the dimensions of respective antenna array, the antenna array being regarded as a matrix X ∈ C 2N x x M x describing the excitation in the aperture of the antenna elements with polarization A and polarization B, the partial antenna array being regarded as a matrix Z ∈ C 2N z x M z; forming (S10 4) virtual antenna elements corresponding to the partial antenna array Z, thereby reducing the full antenna aperture of the antenna array X along the dimension M by means of a reduction matrix Q and then along the dimension N by means of a reduction matrix R, wherein Q ∈ C 2M x x 2 M z and R ∈ C 2N x x 2 N z, wherein the virtual antenna elements are formed by the reduction matrices Q and R being applied to all antenna elements of the antenna array X; expanding the partial antenna array including determining weight factors W p applied to the virtual antenna elements which connect the virtual antenna elements to a greater number of physical antenna elements than the partial antenna array such that the virtual antenna elements at least partly utilize the full antenna aperture, wherein expanding the partial antenna array comprises: i) determining (S106a) the weight factors for a weight matrix W v ∈ C 2N z x M z, where W v is obtained for the beam shape to be used for transmission of the signal; ii) expanding (S106b), using the reduction matrices Q and R, the weight matrix W v into a weight matrix W p ∈ C 2N x x M x such that the virtual antenna elements at least partly utilize the full antenna aperture; and iii) applying (S106c) the weight matrices to the virtual antenna elements; and i) determining (S106a) the weight factors for a weight matrix W v ∈ C 2N z x M z, where W v is obtained for the beam shape to be used for transmission of the signal; ii) expanding (S106b), using the reduction matrices Q and R, the weight matrix W v into a weight matrix W p ∈ C 2N x x M x such that the virtual antenna elements at least partly utilize the full antenna aperture; and iii) applying (S106c) the weight matrices to the virtual antenna elements; and initiating transmission of the signal using the array of the virtual antenna elements while applying the determined weight factors W p.