The invention relates to an electrically tunable antenna. Multiple RCUs are inserted into an antenna housing for controlling multiple phase shifters. The multiple RCUs are cascaded in the antenna housing, the antenna is internally provided with a PCB, and the circuit board is provided with multiple interfaces which are electrically connected with each other. Each RCU is corresponding provided with a conductive probe; and the conductive probe of each RCU is electrically connected with a corresponding interface on the PCB in the antenna so as to connect the RCUs in series, and accordingly, serial connection of the multiple RCUs of a multi-port electrically tunable antenna in a base station antenna is realized.