Characteristic Modes Analysis of Finite Periodic Array With Object Using Entire Domain Basis Function Method and ACA

In this letter, the entire domain (ED) basis function method is applied to the modes analysis of the composite finite periodic array-object. To construct the ED basis functions, the modes analysis of the array cell and object are performed, respectively. The eigenvalues and eigencurrents are obtained. The ED bases on the cell and the object are constructed using a few eigencurrents. Then, the reduced generalized eigenvalue equation (GEE) based on the ED bases will be obtained. By solving the equation, the characteristic modes of the composite structure can be analyzed. To reduce the fill-in time of matrices in the GEE, the adaptive cross approximation is introduced. Numerical results validate the accuracy of the proposed method. Moreover, the CPU time is dramatically reduced.