Wideband digital beamforming by implementing digital fractional filter at baseband

Wideband digital beamfoming (WDBF) is a very important technology to improve the detection performance of radar and other remote sensing systems. The conventional DBF method cannot be applied directly in wideband system because of the aperture effect. This study proposes a new approach to fundamentally solve the aperture effect and achieve WDBF in time domain by using digital fractional delay (FD) filter at baseband to accurately compensate the aperture fill time. This WDBF method is applicable to the transmitting and receiving WDBF of any wideband array signal. Besides, to improve its realizability in engineering, implementing FD filter at subarray level is also discussed.