A Nested Array Geometry with Enhanced Degrees of Freedom and Hole-Free Difference Coarray

This paper presents a new extended nested array geometry with enhanced degrees-of-freedom (DOFs) and a hole-free difference coarray for Direction-of-Arrival (DOA) estimation applications. The array is developed by distributing the sensor of the dense section of the nested array to the nested array's outer subarray while retaining a hole-free difference coarray. The rendered extended nested array has enhanced array aperture and a hole-free difference coarray compared to most existing nested array configurations. Moreover, the proposed array has a closed-form expression for array sensor location and reduced mutual coupling due to sparsely located sensors. Numerical simulations show that the proposed array offers improved DOA estimation resolution than other conventional sparse arrays due to the enhanced aperture.