US Patent 11980915 Ultrasonic transmission structure

Disclosed is an ultrasonic wave transmission structure which is provided on a path of ultrasonic waves to amplify incident ultrasonic waves. The ultrasonic wave transmission structure includes: multiple rings each provided with a body portion having a different radius from other body portions and spaced apart from another body portion adjacent thereto and a slit disposed between adjacent body portions; and a membrane disposed in the multiple rings, wherein the mass of the membrane is adjusted to vary a resonant frequency in multiple sub-membrane regions.