Sparse Rectangular Array with Reduced Mutual Coupling for Active Sensing

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 uniform array, despite having significantly fewer sensors. However, even sparse arrays may have many closely spaced elements, which can deteriorate the array performance through mutual coupling. This paper proposes a novel sparse planar array with very few unit element displacements for reducing mutual coupling. This Concentric Rectangular Array (CRA) is designed for active sensing tasks, such as radar and medical ultrasound, in which the same elements are used for both transmission and reception. The properties of the CRA are compared to two established sparse arrays: the Boundary Array and the Minimum-Redundancy Array (MRA). In some cases, the CRA is the MRA with the fewest closely spaced elements.