Radiation force calculations for ultrasonic fields from rectangular weakly focusing transducers

Knowledge of the theoretical relation between acoustic radiation force and ultrasonic power is important for measuring the emitted power, particularly from medical ultrasonic equipment, using a radiation force balance. A far-field method is applied to calculate the radiation force exerted by rectangular field types on a large absorbing target in a nonabsorbing fluid. This is an extension of previous work on fields with circular symmetry. Pistonlike, apodized, and weakly focusing transducer behavior including diffraction effects is dealt with. If diffraction is neglected, i.e., in the geometric or high-frequency limit, the result can be given as a closed-form expression.