Reduced redundancy arrays for detection and direction finding over a wide frequency range

Array design plays a key role in the performance of radio receivers used to detect signals and estimate their direction of arrival. Non-uniform arrays are used to meet conflicting requirements for large aperture and closely spaced elements, but selecting the best array is difficult when a receiver operates over a wide range of look-angles and signal frequencies. Minimum Redundancy Arrays (MRA) have narrow beamwidth, but sidelobe levels are somewhat high for detection using super-resolution array processing techniques. In addition, the MRA is physically large, often exceeding available space. This paper introduces a design called the Reduced Redundancy Array (RRA); a generalization of MRA's with antenna aperture as a design parameter, allowing the designer to trade beamwidth and sidelobe level. Design rules are described, and it is shown by example that MRA's have good performance over a wide range of frequencies and look-angles.