Fig. 6

Pressure field simulations: a Transducer alone; b Transducer with cone; c Transducer with cone and membrane uninflated; d Transducer with cone and membrane inflated. Output pressure fields in a, b and c were normalized to that of d, where the maximal pressure (P_max) at the focus was found. e Comparison of the simulations (Sim) and hydrophone measurements (Exp): transducer alone (FF); transducer with cone (Cone); transducer with cone and membrane non-inflated (FM); transducer with cone and membrane inflated (IM). Values represent normalized acoustic pressures at the focus to those with the inflated membrane, for both the simulations and the hydrophone measurements. All values, simulated and measured, were normalized to that occurring at the maximum power of 1.5 W with the inflated membrane