Near-field broadband signal DOA estimation based on uniform concentric circular array

This paper proposes a near-field broadband directional-of-arrival (DOA) estimation method using frequency-invariant uniform concentric circular array (UCCA). The principle of the method is to use inverse discrete Fourier transform (IDFT) to convert the received signal to phase mode signals, which are then multiplied by near-field compensation factors to rectify the signal distortion caused by the near-field effect. The resultant phase mode signals are then filtered by a series of finite impulse response (FIR) filters to get frequency invariant response of the array. The proposed near-field broadband UCCA is of frequency-invariant far-field response, which make it possible that the method of far-field narrowband DOA estimation method can be extended to the near-field broadband case. The design example shows that the DOA estimation using the proposed near-field frequency-invariant UCCA has a significant performance improvement over several other methods.