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

Abstract

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 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. Index Terms-Contour deformation, contour-fast Fourier transform (FFT), Green's function, large irregular arrays, macro basis function (MBF), method of moments (MoM), printed antenna, spectral domain method.

Efficient array synthesis of printed arrays including mutual coupling

“…• Interaction in homogeneous medium using Interpolatory technique [19], • Interaction in remaining part (from which homogeneous contribution is subtracted) using Contour-FFT (C-FFT) [20].…”

“…The difference between this approach and others mentioned above is the type of elements, which are printed bowties, being more practical. Moreover, the effect of mutual coupling is included as well by the implementation of fast simulation technique [19], [20] to analyze the array. At each iteration of the optimization, the fast full-wave tools are called to calculate the embedded element patterns of each antenna, which will be introduced into the convex optimization routine to take into account the interaction between elements in the array.…”

Fast and Accurate Simulation Technique for Large Irregular Arrays

“…Nevertheless, the impedance matrix filling time remains O((N a N e ) 2 ), the same as for the original MoM, which is prohibitive for large arrays. To overcome this obstacle, different techniques have been proposed, such as the multipole expansion algorithm [20], [21], the interpolatory technique [22], the perturbation technique based on the domain Green's function [23], or the combination of multipole and Contour-FFT approaches for printed structures [24]. The multipole expansion, however, suffers from the instability of near-field interaction, which appears when antennas are too close to each other, i.e.…”