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. 2022:29:2457-2461.
doi: 10.1109/LSP.2022.3224834. Epub 2022 Nov 28.

Alias-Free Arrays

David Tucker  1 , Shen Zhao  2 , Rizwan Ahmad  3 , Lee C Potter  1
Affiliations

Alias-Free Arrays

David Tucker et al. IEEE Signal Process Lett. 2022.

Abstract

Nonuniform array geometries provide freedom for increased aperture and reduced mutual coupling. A necessary and sufficient condition is given for an array of isotropic sensor elements to be unambiguous for any specified set of directions of arrival. The set of unambiguous spatial frequencies is shown to be a parallelepiped, admitting simple geometrical interpretation. Results are used in design of linear, planar, and 3D arrays.

Keywords: array design; direction of arrival; nonuniform linear array; phase unwrapping; planar array.

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Figures

Fig. 1.
Fig. 1.
(a) For a uniform circular array of six sensors with λ spacing, illustration of the lattice Λ, a basis V, a fundamental parallelogram, and the disc of all DoAs, ℬ2, translated periodically per the lattice. In this case, the translated discs intersect, and the array is aliased. (b) The lattice and shifted ℬ2 for a four-sensor planar array that is alias-free, despite a minimum sensor separation of 0.855λ. (c) A second four-sensor planar array in which ℬ is the set of0020DoAs with ∣θ∣ ≤ 60°; the array is alias-free on ℬ.
Fig. 2.
Fig. 2.
For a bi-tetrahedral (a) array of five sensors, (b) illustration of a fundamental parallelepiped and the sphere of all DoAs, ℬ3, translated to the center of the parallelepiped. Spheres translated to lattice points are merely tangent; the array is alias-free other than three pairs of ambiguous DoAs.
See this image and copyright information in PMC

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