Sparse array systems for ultralight UAV radar

Sparse array imaging systems (developed in ultra sound medical imaging) using a co array can be deployed on small UAVs to eliminate grating lobes on a wideband radar. This allows the use of thin film antennas under the aircraft wing using a split transmit and receive aperture. Simulations show side lobes equivalent to an array of 2 times the linear dimension. Apodization reduces sidelobes to -100dB, but a secondary lobe is apparent at 0.5 - 0.8π. Z Transform apodization will reduce the secondary lobe. It can be eliminated entirely using sub kernel convolution with the Z transform.