This paper proposes a calibration method for array antennas which includes the mutual coupling between antenna elements. Conventional methods such as the rotating element electric field vector (REV) method for the elements of array antennas do not account for the mutual coupling between elements. When an antenna calibration is not performed adequately, the radiation intensity of the radio waves in the undesired direction increases, causing interference with other satellites which are not intended. In order to overcome this drawback, a model of an array antenna including a coupling between antenna elements is constructed. Using this model, the estimation problem of the effect of the mutual coupling is formulated as formulation problem. Finally, a calibration method based on the solution of the optimization problem is derived.