Application of the Active Element Pattern Method for Calculation of the Scattering Pattern of Large Finite Arrays

This letter extends the concept of the active element pattern method that is used to solve the array radiation problem when scattered fields of large finite arrays are calculated. We name this method the original induced element pattern method (OIEPM). The theoretical derivation of the method is presented. In addition, to overcome the limitation and simplify the operation of the OIEPM, an improved induced element pattern method (IIEPM) is proposed, which transforms the large array calculation problem into two small array problems. Unlike the OIEPM that requires calculation of the induced element pattern (IEP) of all the elements of the subarray, the IIEPM merely needs to calculate the fully scattered field of two small arrays. Meanwhile, the effects of the mutual coupling between elements and the edge diffraction are rigorously taken into account. Compared to other numerical and active (or induced) element pattern methods, the IIEPM can greatly reduce the computational cost and simplify the operational procedure. Examples of microstrip patch antenna arrays are analyzed to assess the accuracy and generality of the IIEPM. Numerical examples show that the scattering patterns calculated by the IIEPM and those simulated by the HFSS are in good agreement.