MLFMA Analysis of Waveguide Arrays with Narrow-wall Slots

The radiation characteristics of waveguide array with narrow-wall slots are analyzed using the multilevel fast multipole algorithm (MLFMA) combined with the near-field preconditioner. Since only the free space Green's function is required and no approximation is assumed, the proposed method is considered to be theoretically and numerically more accurate than existing methods that utilize asymptotic methods, such as method of moments (MoM) with the magnetic field integral equation (MFIE) and hybrid methods of MoM and boundary element method (BEM). In addition, the low complexity of the MLFMA is especially favorable for fast calculation of the large-scale waveguide arrays. The experimental results validate the algorithm.