Wideband beampattern synthesis using single digital beamformer with integer time delay filters

In this chapter, we proposed a novel time-domain wideband DBF method that utilizes one set of amplitude-phase weighting and ITDF to control the beam shape over the whole bandwidth. To suppress sidelobe interferences in a spectrally crowded environment, we synthesized low nulls over the whole bandwidth via minimizing the maximal null level at three specially chosen frequency bins. Two competitive algorithms were proposed to address the resulting non-convex problem, suitable for different scenarios. Finally, the effectiveness of the proposed WDB was validated through numerical simulations. As the focus of this work is on the theoretical development of digital wideband beamforming, future research will involve the practical implementation of the proposed design using DSP chips or field programmable gate array (FPGA). Other potential researches derived from this work include extending the proposed framework to consider joint design of weighting coefficients and antenna locations to achieve the desired wideband or ultra-wideband beampattern [7].