Computation and Properties of the Wide-Band Beam Pattern

The definition, computation and properties of the beam pattern of an ultrasonic imaging system working under wide-band conditions are addressed. After defining the beam pattern as the total energy of the beam signals, a fast and flexible method to compute such a beam pattern is proposed that works correctly for whatever weighting window, pulse shape, and inter-element spacing. Moreover, the proposed method is extended to the computation of the beam pattern area, allowing to asses the effects of different weighting windows and pulse waveforms. In particular, if a rectangular pulse envelope is adopted, this paper demonstrates that, like under narrow-band conditions, the beam pattern area is minimum when a uniform weighting window is applied.