Sparse Active Rectangular Array With Few Closely Spaced Elements

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.

Next Generation NDE Sensor Systems as IIoT Elements of Industry 4.0

“…[18]. With a growing research interest in sparse techniques due to the rise of the CS theory, the optimal array design and the corresponding signal processing algorithms have been an active research topic since then [19][20][21][22]. CS itself was applied to medical ultrasound in various flavors more recently, e.g., in [23][24][25][26].…”

Hybrid Beamforming for Active Sensing Using Sparse Arrays

“…5 (a) [29]. Note that other sparse array configurations with this property also exist [30]. We ignore mutual coupling and assume that the array elements have identical sinusoidal gain patterns g(ϕ, θ) = cos ϕ sin θ. Consequently, the (transmit and receive) steering vectors assume the form a(ϕ, θ) = cos ϕ sin θ exp(jπ(d x sin ϕ sin θ + d z cos θ)), where d x ∈ Z N and d z ∈ Z N are the x and z coordinates of the elements normalized by λ/2, as illustrated in Fig.…”

Sparse Low-redundancy Linear Array with Uniform Sum Co-array

“…The d-spacing multiplicity, S(d), enumerates the number of inter-element spacings of a given length d in the array. For linear arrays, this simplifies to the weight or multiplicity function of the difference co-array [3,6].…”

“…Arrays are often also designed to have few closely spaced sensors. This may improve performance in the presence of mutual coupling [4][5][6][7], since the coupling magnitude is usually inversely proportional to the inter-element distance [8].…”