This paper proposes a novel method for calculating the radiation and scattering patterns of large arrays.Approximate expressions of the proposed method are derived based on the active element pattern technique and the principle of superposition.With the expressions

the large array analysis problems are converted into two simplified small array problems and the computational cost is considerably reduced.In addition

the effects of the mutual coupling and the surrounding array environment are rigorously accounted for.Example arrays of microstrip patch antennas are analyzed to assess the proposed method.A good agreement between the results calculated by the proposed method and the ones simulated by HFSS validates the accuracy of the proposed method.