The present invention relates to an antenna assembly. The antenna assembly comprises a feed board, a backplane, and a calibration board. A plurality of radiating elements are mounted on the feed board and extend forwardly from the feed board. The feed board is mounted on a first major surface of the backplane, and the calibration board is mounted on a second major surface of the backplane opposite the first major surface. The antenna assembly further includes a conductive structure, which extends through openings in at least two of the feed board, the backplane and the calibration board so as to electrically connect a first transmission line on the calibration board with a second transmission line on the feed board. The antenna assembly according to embodiments of the present invention can also achieve high integration and miniaturization of the overall antenna construction. Further, the present invention relates to a base station antenna comprises an antenna assembly.