Fast spectral domain analysis of large finite microstrip patch arrays

The scattering and radiation from large finite arrays of microstrip patches is analyzed by an improved spectral-domain moment method. Based on the electric field integral equation (EFIE) and using rooftop expansion and testing functions in a uniform discretization scheme, the elements of the resulting equation system are represented by inverse Fourier integrals. In the new approach, the application of the two-dimensional sampling function leads to equivalent finite integral expressions which are efficiently evaluated using Filon type quadrature rules in combination with the FFT algorithm. This reduces the number of sample points in the spectral domain drastically. The final discrete equation system is solved iteratively using the biconjugate gradient-FFT (BCG-FFT) algorithm. This results in a fast and accurate computation code appropriate for application on a PC. Several numerical examples for arrays up to N=32/spl times/16 patches are presented demonstrating the versatility of this technique.