An antenna array system (300, 500) comprising: a plurality of transmission lines (321, 331); a plurality of transmitters; a plurality of transmit antenna elements, wherein each antenna element of said plurality of transmit antenna elements is connected, respectively, via one transmission line of said plurality of transmission lines to one of said plurality of transmitters; a plurality of receivers; a plurality of receive antenna elements, wherein each receive antenna element of said receive antenna elements is connected, respectively, via one transmission line of said plurality of transmission lines to one receiver of said plurality of receivers; at least one dedicated transmitter connected to at least one dedicated receiver via a dedicated calibration transmission line; and at least one processor in communication with said plurality of transmitters and with said plurality of receivers, said processor being configured to: obtain a delay value of a dedicated calibration transmission line of a reference antenna array system; measure the delay value of the dedicated calibration transmission line of the antenna array system; evaluate a delay change value Δ delay ( x cal) by subtracting the delay value of the dedicated calibration transmission line of the reference antenna array system from the delay of the dedicated calibration transmission line of the antenna array system; calculate compensation values for cancelling the incurring electrical length change of each pair (i,j) of transmit-receive transmission lines of the antenna array system wherein the calculation is based on the evaluated delay change Δ delay ( x cal); and calibrate the antenna array system using the calculated compensation values. a plurality of transmission lines (321, 331); a plurality of transmitters; a plurality of transmit antenna elements, wherein each antenna element of said plurality of transmit antenna elements is connected, respectively, via one transmission line of said plurality of transmission lines to one of said plurality of transmitters; a plurality of receivers; a plurality of receive antenna elements, wherein each receive antenna element of said receive antenna elements is connected, respectively, via one transmission line of said plurality of transmission lines to one receiver of said plurality of receivers; at least one dedicated transmitter connected to at least one dedicated receiver via a dedicated calibration transmission line; and at least one processor in communication with said plurality of transmitters and with said plurality of receivers, said processor being configured to: obtain a delay value of a dedicated calibration transmission line of a reference antenna array system; measure the delay value of the dedicated calibration transmission line of the antenna array system; evaluate a delay change value Δ delay ( x cal) by subtracting the delay value of the dedicated calibration transmission line of the reference antenna array system from the delay of the dedicated calibration transmission line of the antenna array system; calculate compensation values for cancelling the incurring electrical length change of each pair (i,j) of transmit-receive transmission lines of the antenna array system wherein the calculation is based on the evaluated delay change Δ delay ( x cal); and calibrate the antenna array system using the calculated compensation values. obtain a delay value of a dedicated calibration transmission line of a reference antenna array system; measure the delay value of the dedicated calibration transmission line of the antenna array system; evaluate a delay change value Δ delay ( x cal) by subtracting the delay value of the dedicated calibration transmission line of the reference antenna array system from the delay of the dedicated calibration transmission line of the antenna array system; calculate compensation values for cancelling the incurring electrical length change of each pair (i,j) of transmit-receive transmission lines of the antenna array system wherein the calculation is based on the evaluated delay change Δ delay ( x cal); and calibrate the antenna array system using the calculated compensation values.