Analysis of mutual coupling in large arrays of printed antennas using Contour-FFT

An efficient mutual coupling analysis method is presented for large arrays of printed antennas. Mutual coupling effects play an important role when one deals with large arrays, as the near-field and far-field characteristics of an individual element get drastically altered in such conditions. These effects are characterised through the embedded element patterns and through the port currents when a single element is excited while all the other elements in the array are terminated with matched loads. We demonstrate that, with the help of the Contour-FFT Macro Basis Function (MBF) approach combined with the MBF-based multipole approach for homogeneous medium, mutual coupling effects can be accurately analyzed with N log₂ N complexity for substrate related interactions. Moreover, a newly developed method of CFFT-based iterative solution for arbitrarily printed structures is briefly explained, and several results are presented. An excellent comparison is reported between results obtained with the proposed method and with reference solutions.