An antenna assembly comprises a circuit board formed with an antenna, a coaxial cable and a conductive film. The circuit board has an edge, a first pad and a second pad. An outer conductor of the coaxial cable has an exposed portion which is exposed from an outer cover of the coaxial cable over a predetermined area. The exposed portion is connected with the second pad. In a second direction perpendicular to a first direction, a center of the coaxial cable is positioned at a predetermined position. The conductive film is fixed on the circuit board. The conductive film has a main portion and at least one extending portion. In the predetermined area, the at least one extending portion and the second pad are aligned in the first direction. The at least one extending portion extends from the main portion over the predetermined position in the second direction.