Broadband beamforming has been an important issue on antenna array processing due to many practical demands on communication, radar, or sonar applications. Although several effects deteriorating array performance have been addressed for narrowband beamforming, few of them are considered for the broadband scenario. Besides, the definition of output signal-to-interference plus noise ratio (SINR) and the way to simulate broadband signal sources are usually vague, which further obstructs the development of broadband beamforming. In this paper, the performance of discrete Fourier transform (DFT) beamformers operating in block processing and sliding window modes are investigated when the correlation matrices are known or estimated by finite data samples. The output SINR of DFT beamformers is well-defined, and the generation of broadband signals is clearly introduced. Simulation results with respect to the signal bandwidth, the number of frequency bins, and the number of data samples are presented for illustration and comparison.
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