We apply the simulated annealing optimization algorithm
to linear arrays to be used in ultrasound imaging
systems under wide-band operation. We address
the optimization problem of both dense and sparse
wide-band arrays. In the first case, we compare the
optimized beam pattern with that obtained with a
classical shading function. In the latter case, we consider either the
optimization of the layout (element
positions and weights) or the optimization of only
element positions of sparse arrays which generate a
beam pattern with minimum side-lobe level. We show
that an about -7-dB further reduction of the side-lobe
level can be achieved with a wide-band sparse
array optimization, with respect to a narrow-band
optimization. The performances of the optimized arrays are
verified on some phantom images.