Optimization of a Coherent Dual-Beam Array Feed Network for Aperiodic Concentric Ring Antennas

Armando Arce,Enrique Stevens-Navarro,David H Covarrubias,Francisco R Castillo-Soria,Ulises Pineda-Rico,Marco Cardenas-Juarez

doi:10.3390/app11031111

Abstract

A dual-beam coherent feeding system design approach with a non-uniform layout on a concentric ring array is described and synthesized. In this case, the feeding system is based on a reconfigurable topology composed of a set of alternated power dividers and combiners, providing coherent in-phase outputs. Thus, in this paper, a two-beam architecture based on a coherent feeding system formed by a set of intercalated input signals feeding each circular ring in a non-uniform antenna array with multi-beam shaping and steering features is analyzed. The task of optimizing the aperiodic layout on the shared aperture based on the radii of the circular rings is realized by the differential evolution method. Numerical experiments grounded in antenna synthesis validate the capabilities and improved performance of the proposed dual-beam configuration with a non-uniform layout in contrast with its uniform counterpart, with enhanced performance on average by up to −6.1 dB for sidelobe level and 3.5 dB for directivity. Additionally, the results show a significantly less complex two-beam feeding network in contrast with the case of a typical electronically scanned array—in this proposal, each direction of maximum radiation is conformed and scanned with approximately half of the control inputs.

Highlights

Arrays of antennas are a fundamental actor and base in wireless communication systems, where a group of radiators can perform advanced features synthesizing one or more beam patterns of arbitrary shape
The simulation setup is described alongside the numerical results obtained from the two-beam C-beamforming network (BFN) configuration for applications in aperiodic concentric ring arrays (ACRAs)
One main objective under this scenario is to estimate the dual-beam pattern generated by the antenna system, as well as the performance in a comparative study with a uniform layout scenario in order to compare the results

Summary

Introduction

Arrays of antennas are a fundamental actor and base in wireless communication systems, where a group of radiators can perform advanced features synthesizing one or more beam patterns of arbitrary shape. Increasing the number of antennas can improve the antenna system’s capabilities in some cases with multiple shaped and directive beams, power pooling, element redundancy, angular diversity, and electronic beam scanning (phased arrays) These multi-beam antennas are not a single entity and their function relies on an underlying feeding system, usually a beamforming network (BFN) subsystem that is an essential component for feeding and combining the array element’s signals [1]. This paper presents a dual-beam analysis of an antenna system’s performance that exploits a non-uniform aperture with concentric ring antennas, employing a minimalistic architecture based on coherently radiating periodic structures with multi-beam steering capabilities. In this approach, the antenna system is optimized in such a way that the radii on the antenna array are improved by a well-known evolutionary optimizer.

Aperiodicity in Concentric Ring Arrays

Coherent BFN Model

Optimization Tool

Numerical Results

Conclusions