An Fft-based Approach in Acceleration of Discrete Green’s Function Method for An- Tenna Analysis

In this paper, the fast Fourier transform (FFT) to perform spatial convolutions of the time domain discrete Green’s functions (DGF) method related to the analysis of the antenna with more than one dimension has been proposed. For this aim, the discrete Green’s functions and the currents on the antenna have been appropriately defined periodic so as to use the zero padded fast Fourier transform. The computational complexity of this approach is O(NwNxNyNz log(NxNyNz)), contrary to O(NwN xN 2 y N 2 z ) for direct implementation of the convolutions. Simulation results demonstrate the great efficiency of the FFT-based spatial convolutions in the modeling of planar antennas.