K-Space Beamforming for an Array of Quantum Sensors

Abstract: In this paper we present a novel beamforming technique that can be used with an array of quantum sensors. The transmit waveform is a short-duration frequency comb constructed using a finite number of sinusoidal tones separated by a fixed offset. Each element in the array is tuned to one of the tones. When the radiated signal is received by the aperture, each array element accumulates phase at a different rate since it is matched to only one frequency component of the comb waveform. The result is that over the duration of the received pulse, progressively higher spatial frequencies are generated across the aperture. By summing the outputs of all the array elements, a strong peak is created in k-space at the precise time instant when the phases of all the array elements align. The k-space coordinates of the output can then be transformed to angles as discussed in the paper. This paper also describes how to set waveform parameters and the separation between array elements. A desirable advantage of the proposed approach is that the received signal is amplified by the coherent integration gain of the entire spatial aperture.