Towards beamforming for UWB signals

Beamforming for UWB signals has some special properties that are different from the narrowband case. The investigation of ideal time-delay beamforming for short pulses shows a striking feature, namely the absence of grating lobes in the beampattern. This means that the spacing of the array elements is not limited by half of the wavelength, hence high resolution can be achieved with only a few array elements. Further, the beampatterns sidelobe structure is mainly dependent on the impulse shape. Concerning digital beamforming, a realistic assumption is that only filters with a few coefficients can be used, due to the very high sampling rate needed for digital processing of UWB signals. But again, the use of broadband pulses allows to obtain acceptable digital beampatterns with low complexity. This means that a realization of digital beamforming for UWB signals might be possible in the near future.