Contour-FFT Based Spectral Domain MBF Analysis of Large Printed Antenna Arrays

A fast spectral-domain method is proposed to evaluate the reaction terms between the macro basis functions in regular and non-regular arrays made of identical printed antennas. The presented technique first exploits the filtering capabilities of the macro basis functions in the spectral domain. The method is then strongly accelerated with the help of a newly formulated fast Fourier transform (FFT)-based technique, which is applicable to a contour integration in the complex plane. We name the method as contour-FFT (C-FFT). Besides an effective homogeneous medium term treated with multipoles, a computational complexity of order Nlog2N is achieved for the tabulation of substrate-related reaction terms for any possible relative positions. The complexity of the proposed method is independent from the complexity of the elements. Numerical results obtained with the proposed method are compared with those from a pre-validated reference solution based on the traditional macro basis functions technique; an excellent agreement is observed.