US Patent 8450907 Sound generator for use in parametric array

A sound generator includes a transducer converting electric energy to mechanical energy, a mechanical amplifier mechanically amplifying a vibration generated in a piezoelectric component of the transducer, and a radiation plate radiating a sound wave from a signal amplified by the mechanical amplifier, wherein the radiation plate includes a first step having a height for compensating for a first resonance frequency and a second step having a height for compensating for a second resonance frequency.