Sparse Active Rectangular Array with Few Closely Spaced Elements

TL;DR

This paper introduces a novel Concentric Rectangular Array (CRA) for active sensing that minimizes closely spaced elements, improving performance and reducing mutual coupling effects compared to existing sparse array designs.

Contribution

The paper proposes the CRA, a new sparse array configuration with few closely spaced elements, optimized for active sensing applications and shown to outperform traditional arrays in certain dimensions.

Findings

CRA is the minimum-redundancy array with fewest unit displacements for some dimensions

CRA reduces mutual coupling effects compared to other sparse arrays

Numerical analysis confirms CRA's superior performance in specific configurations

Abstract

Sparse sensor arrays offer a cost effective alternative to uniform arrays. By utilizing the co-array, a sparse array can match the performance of a filled array, despite having significantly fewer sensors. However, even sparse arrays can have many closely spaced elements, which may deteriorate the array performance in the presence of mutual coupling. This paper proposes a novel sparse planar array configuration with few unit inter-element spacings. This Concentric Rectangular Array (CRA) is designed for active sensing tasks, such as microwave or ultra-sound imaging, in which the same elements are used for both transmission and reception. The properties of the CRA are compared to two well-known sparse geometries: the Boundary Array and the Minimum-Redundancy Array (MRA). Numerical searches reveal that the CRA is the MRA with the fewest unit element displacements for certain array dimensions.