Abstract
A novel method is proposed for spectrally shaping the beamforming
weights quantization error at the sub-array layer where the in-band
distortion intends to move into a position where the sub-array factor
has high attenuation. To do that, the sub-array factor or the
composite sub-array factor is tiled by the periodicity of the
ultimate-layer array factor. Then, the digital filter layout is
designed based on the superposition of all tiles intersecting with the
visible region of the overall array factor (O-AF), and the O-AF is
spectrally shaped to minimize the number of bits quantifying the
beamforming weights. The method is investigated for analog, digital,
and hybrid array beamforming with multi-layer overlapped sub-array
systems of different sizes and shapes. Its performance is promising
and potent in alleviating the overall array factor distortion in all
cases.