An electronic device comprising: a display unit (151, 340); a printed circuit board, PCB, below the display unit; an array antenna including a transparent electrode material and being disposed within the display unit (151, 340); and a radio frequency integrated circuit, RFIC, electrically connected to the array antenna, wherein the array antenna includes a plurality of antenna elements (200, 500) each including: first and second sides perpendicular to each other disposed slopingly at a predetermined angle with respect to one side of the display unit (151, 340); and a feeding part (210, 220) including first and second feeding lines (510, 520) connecting the antenna element and the RFIC, wherein the RFIC is disposed on the PCB below the display unit, wherein the RFIC is further disposed on a flexible printed circuit board, FPCB, connecting the display unit and the printed circuit board, such that the RFIC and the array antenna have an electric connection by the FPCB between the feeding part (210, 220) and the RFIC, wherein the display unit (151, 340) comprises a first layer and the FPCB comprises a second layer, wherein each of the antenna elements is disposed on the first layer, wherein the first and second feeding lines (510, 520) are disposed on the second layer below the first layer, and wherein electrical signals from the first and second feeding lines (510, 520) are slot-coupled to the antenna element through a slot in which a ground pattern is removed on a ground plane on a third layer between the first and second layers (550, 560). a display unit (151, 340); a printed circuit board, PCB, below the display unit; an array antenna including a transparent electrode material and being disposed within the display unit (151, 340); and a radio frequency integrated circuit, RFIC, electrically connected to the array antenna, wherein the array antenna includes a plurality of antenna elements (200, 500) each including: first and second sides perpendicular to each other disposed slopingly at a predetermined angle with respect to one side of the display unit (151, 340); and a feeding part (210, 220) including first and second feeding lines (510, 520) connecting the antenna element and the RFIC, wherein the RFIC is disposed on the PCB below the display unit, wherein the RFIC is further disposed on a flexible printed circuit board, FPCB, connecting the display unit and the printed circuit board, such that the RFIC and the array antenna have an electric connection by the FPCB between the feeding part (210, 220) and the RFIC, wherein the display unit (151, 340) comprises a first layer and the FPCB comprises a second layer, wherein each of the antenna elements is disposed on the first layer, wherein the first and second feeding lines (510, 520) are disposed on the second layer below the first layer, and wherein electrical signals from the first and second feeding lines (510, 520) are slot-coupled to the antenna element through a slot in which a ground pattern is removed on a ground plane on a third layer between the first and second layers (550, 560). first and second sides perpendicular to each other disposed slopingly at a predetermined angle with respect to one side of the display unit (151, 340); and a feeding part (210, 220) including first and second feeding lines (510, 520) connecting the antenna element and the RFIC, wherein the RFIC is disposed on the PCB below the display unit, wherein the RFIC is further disposed on a flexible printed circuit board, FPCB, connecting the display unit and the printed circuit board, such that the RFIC and the array antenna have an electric connection by the FPCB between the feeding part (210, 220) and the RFIC, wherein the display unit (151, 340) comprises a first layer and the FPCB comprises a second layer, wherein each of the antenna elements is disposed on the first layer, wherein the first and second feeding lines (510, 520) are disposed on the second layer below the first layer, and wherein electrical signals from the first and second feeding lines (510, 520) are slot-coupled to the antenna element through a slot in which a ground pattern is removed on a ground plane on a third layer between the first and second layers (550, 560).