On the Fast Analysis of Finite Printed Arrays Supporting Eigenmodes

In this paper, we demonstrate that the Array Scanning Method-Macro Basis Function approach, named as ASM-MBF method remains very accurate for the analysis of printed arrays in the presence of eigenmodes. The eigenmode condition occurs for the phase shifts in "spectral domain" where determinant of the Method-of-Moments (MoM) impedance matrix vanishes. Under this condition, at least one of the eigenvalues of the infinite-array impedance matrix vanishes and the corresponding eigenvector represents the eigenmode current distribution in terms of elementary basis functions. The resulting set of MBFs are used to analyse the specific array condition supporting the eigenmodes in terms of the port currents.