Null steering in irregularly spaced sparse antenna arrays using aperture distributed subarrays and hybrid optimiser

Abstract

Sparse antenna arrays with irregularly spaced elements are increasingly being used in large array applications such as radio astronomy and radar. These antenna arrays may consist of hundreds of elements and therefore optimisation of these arrays becomes computationally expensive. This study proposes a novel solution to the problem of null synthesis in such arrays, where nulls are formed in prescribed locations for two‐dimensional irregular sparse antenna arrays. The technique is based on a subarray and hybrid synthesis solution, where each subarray spans the entire antenna aperture. Single and multiple null formations with array gain maximisation are considered. The technique's effectiveness is demonstrated using evolutionary optimisation algorithms; however, the basic technique can be used with other optimisation methods. The simulation results presented compare the null synthesis performance with and without subarraying and it has shown that the use of subarray results in improved convergence compared with a direct full array synthesis. Furthermore the technique is appropriate for ready application to parallel computer architectures.

Survey of Large-Scale MIMO Systems

“…2. On the other hand, in order to reduce the side lobes of the irregular AA, advanced algorithms relying on subarrays [24], on orthogonal placement [25], or on parasitic AAs [26] can be introduced for improving the beamforming performance of these irregular AAs.…”

High‐power efficiency aperiodic phased array antenna for space‐borne SAR

“…The most critical drawback of the sparse array for space SAR application is that the antenna gain might degrade approximately proportional to the reduction of radiating element number. To address this problem, recent works on the high gain sparse array have been reported [4,[9][10][11][12]. A common strategy of these designs is to utilise different elements with variable apertures or use subarrays, to maximally fill up the entire array aperture.…”

Sector nulling in planar irregular sub‐arrayed sparse array antennas

“…To the best of authors' knowledge, very little or no attention is given to sector nulling in irregular sparse planar antenna arrays. However, [17] addresses the problem of applying the precision nulls in planar sparse antenna arrays. The reported work covers the narrowband nulling in multiple directions but the wide sector and wideband nulling have not been addressed.…”

“…Sub-arrays with smaller numbers of elements converge faster but show compromised nulling performance in terms of average null depths. A hybrid optimisation scheme consisting of a particle swarm optimiser and a sequential quadratic programing (Hy-PSO-SQP) [17] has used to meet the design objectives by tuning the complex array excitations. The proposed method may be applied to achieve two-dimensional (2D) nulls as demonstrated in this communication.…”