New efficient acceleration technique for the calculation of the Green’s functions in rectangular waveguides

In this paper, we have presented a new approach for the efficient calculation of the Green’s functions inside a rectangular waveguide. The idea is to apply the Kummer transformation, using two static terms of the spectral domain Green’s functions, obtained through a Taylor series expansion. Instead of applying the Ewald method to the whole series, it is only applied to the first static series. The other terms are accelerated via the summation by parts technique. We show that using the new strategy, the computational cost is considerably reduced as compared to a standard brute-force application of the Ewald method.