Wideband DoA Estimation Based on Antenna Current Green's Function using RBF Interpolation

In this paper, the concept of the antenna current Green's function is utilized to estimate the Direction of Arrival (DoA) in environments characterized by strong mutual coupling effects and wideband signals.An RBF interpolation technique is proposed to obtain a calibration matrix effective across the frequencies of interest, and it is validated using computational methods.The antenna current Green's function, which is used for calculating the mutual coupling components between elements of the receiving array, is employed to model the received voltage signals.An optimization process is developed to obtain the calibration matrix, which minimizes the difference between the modeled voltage signals and the ideal signals that incorporate only progressive phase delays.For validation, a uniform linear array consisting of 10 half-wavelength dipole antennas operating at 2.4GHz is used as the receiving antenna, and two single dipole antennas serve as the transmitting antennas.Employing the proposed method, RBF interpolation with four calibration matrices spanning frequencies from 1.8GHz to 3GHz demonstrates high resolution for DoA estimation, while linear interpolation, in contrast, yields inferior results.