Mutual coupling analysis of large irregular arrays: From multipole to interpolatory methods

A novel formulation is proposed for the multipole expansion, called Laurent series formulation. It finds applications to the fast calculations of integral reactions between Macro Basis Functions in large planar irregular arrays of identical elements. Indeed, it automatically provides the coefficients of the harmonic-polynomial model of the reactions. A better understanding is also achieved for the minimized impact of the so-called low-frequency breakdown when computing interactions at small distances with the interpolatory method.