This invention belongs to the field of ultrasonic sensing and
microelectromechanical systems (MEMS) packaging technology, specifically relating to a multi-segment acoustic packaging structure and optimization method for a
PMUT ultrasonic
transducer. The multi-segment acoustic packaging structure for a
PMUT ultrasonic
transducer includes a base, a
PMUT chip, and an
acoustic cavity. The
acoustic cavity includes a front cavity section, a tapered transition section, a conduit section, and a waterproof and acoustically permeable membrane. A first minimum gap is formed between the radiating surface of the PMUT
chip and the bottom surface of the front cavity section; a second minimum gap is formed between the waterproof and acoustically permeable membrane and the outlet end of the conduit section. Furthermore, the
acoustic cavity serves as either a
transmitter or a
receiver. When used as a
transmitter, the depth of the front cavity section is greater than that of the front cavity section when used as a
receiver, and the inner
diameter of the conduit section is smaller than that of the conduit section when used as a
receiver. This packaging structure, through optimization of geometric parameters and acoustic characteristics, achieves differentiated performance improvements for the
transmitter and receiver, increasing the transmitted
sound pressure and
directivity, and expanding the bandwidth and receiving angle of the receiver.