Figure 4.

Simulated axial pressures generated by the 32×32 element planar array in Fig. 2. The array is located at z=0 cm and electronically focused at (0,0,10) cm. The reference pressure calculated by the spatial impulse response method is indicated by the solid line, the pressure computed with the angular spectrum approach using an input normal particle velocity plane is represented by the dash-dot line, and the pressure computed with the angular spectrum approach using an input pressure plane is represented by the dashed line.