Multi-Frequency Rational Sparse Array for Direction-of-Arrival Estimation
Yimin Daniel Zhang, Moeness G. Amin · 2023
In this paper, we consider sparse array-based direction-of-arrival (DOA) estimation using multiple frequencies that are associated with coprime rational numbers. By exploiting rational frequencies instead of integer ones as used in the existing literature, the proposed method provides a flexible design of multi-frequency sparse arrays with a reduced frequency separation. We demonstrate that the use of coprime rational frequencies ensures unambiguous DOA estimation, despite that the interelement spacing of the array in each frequency is higher than half-wavelength. We further consider practical selection of the rational frequencies guided by the spatial correlation coefficient.