Systematic approach to sidelobe reduction in linear antenna arrays through corporate‐feed‐controlled excitation

Abstract

A systematic approach to sidelobe reduction of broadside linear antenna arrays by design of corporate feeds implementing non‐uniform excitation is proposed. The approach comprises of the two major stages. First, candidate excitation sets (corporate feeds) are searched among excitation sets which might energize a particular array aperture. The range of the corporate networks is restricted – based on the implementation and performance considerations – to the ones constructed using only T‐junctions with equal power split. The reference for the candidates in terms of the sidelobe level is the uniformly excited and spaced array aperture with the same number of elements. The search is performed over realizable excitations and constrained elements’ spacings using the array factor and the model of excitation amplitudes due to corporate feeding. At the second stage, an excitation providing reduced sidelobes and simple routing is implemented as a microstrip corporate feed within the antenna array model. The entire antenna‐feed circuit is adjusted and validated using numerical optimization and discrete electromagnetic simulations at the high‐fidelity level of description. The proposed feeds and the approach to their systematic design offer flexibility in design of linear antenna arrays without extra complications and allow substantial sidelobe reduction. A demonstration example is provided.

Surrogate‐assisted tolerance analysis of low‐sidelobe linear arrays with microstrip corporate feeds

“…The tree, shown in Figure A, had been found with numerical optimization of a fast model of the feed . T‐junctions of unequal power split, shown in Figure B and 4C) realize the power distribution within the feed.…”

“…Such factors, if not accounted for with electromagnetic (EM) simulations, result in degraded design characteristics, eg, increased sidelobes, broadened major lobes, and decreased total efficiency. Systematic EM‐based approaches to the design of the low‐sidelobe linear microstrip arrays with corporate feeds have been proposed, where the design processes included identification of the optimal feed prototypes, implementation of the feeds with numerical simulation‐based optimization, EM‐based design and optimization of the array aperture, and EM‐based tuning and optimization of the entire array circuits.…”

Surrogate‐assisted design of microstrip corporate feeds integrated with linear microstrip array apertures for required sidelobe levels

“…At step 2, the feed tree, providing the closest approximation of the excitation taper, is searched using numerical optimization where feeds are described in terms of its architectures and junctions' power splits (PSs). In this work, only three‐port T‐junctions, which are matched only at the input, are used.…”

“…Alternatively, standard optimization approaches, mostly population‐based metaheuristics (eg, genetic algorithms, differential evolution, cuckoo search, etc), eg, are of prohibitive numerical costs if used with realistic array models. The surrogate‐based optimization methodology can make EM‐based design of array apertures, feeds, as well as integrated arrays computationally feasible …”

Non-Uniformly Powered and Spaced Corporate Feeding Power Divider for High-Gain Beam with Low SLL in Millimeter-Wave Antenna Array

“…Recently, a non-uniformly spaced corporate feed network was also introduced as a solution to further reduce the SLL of a patch antenna array [ 27 , 28 , 29 , 30 ]. In [ 27 , 28 ], non-uniformly spaced series-fed arrays were introduced to reduce SLL at 9 GHz and 24 GHz, respectively, but these arrays also need to taper the radiating elements.…”