A High Resolution Optimum 2D Coprime Planar Array

TL;DR

This paper introduces a novel two-dimensional sparse array design that enhances signal resolution and degrees of freedom by utilizing virtual arrays and optimized geometry, reducing holes and increasing array aperture.

Contribution

It proposes a new class of rectangular 2D arrays with improved virtual array properties and optimized geometry for better angular resolution and array performance.

Findings

Increased degrees of freedom with fewer sensors.

Contiguous dense difference co-array reduces holes.

Optimized array geometry enhances directivity and suppresses sidelobes.

Abstract

Designing a new class of rectangular two-dimensional sparse array to enhance the signal resolving capabilities with a limited number of sensors has always been a challenge. We explore the non-uniformity of the sparse arrays to enhance the Degrees of Freedom (DOF) by considering the under-determined cases using the concept of the virtual array. In this paper, we propose a two-dimensional novel sparse array configurations to estimate both azimuth and elevation angle of arrival of the signal. We propose a new class of rectangular two-dimensional arrays with sensors on a plane, whose difference co-array can give rise to a virtual two-dimensional planar array with a much larger number of elements, leading to an increase in the fully augmentable range of the array. The difference co-array of the proposed rectangular array gives a contiguous dense structure which leads to a reduction in holes within the planar array as compared to the traditional methods of CPA geometry in which there are many holes present in the outer dimension of the array structure as well as within the array as well. Moreover, we know that the angular resolution of an array is highly dependent on its beamwidth which itself is inversely proportional to array size or effective array aperture. Hence by increasing the array dimension a higher resolution can be achieved. The proposed arrays provide a higher DOF for the given number of physical sensors. Optimization is performed on the proposed geometry to maximize the directivity in the array steering look-up direction by suppressing the sidelobe levels to a greater extent.