Piezo-Electret Capacitive Micromachined Ultrasonic Transducers based on BTO-doped PVDF film

In order to solve the shortcomings of the capacitive micromachined ultrasonic transducer requiring an external bias voltage, the Piezo-Electret Capacitive Micromachined Ultrasonic Transducers was designed. It was based on the capacitive micromachined ultrasonic transducer. The piezoelectric/electret material layer was added to the diaphragm of the capacitive micromechanical ultrasonic transducer, then the electret was used to store charge to provide an electrostatic field, and the signal was enhanced by the positive and inverse piezoelectric effect. Therefore, it could reduce or even remove the bias voltage required for the transducer. After experimental verification, the new transducer can transmit ultrasonic waves without external bias voltage, and complete the reception of ultrasonic waves with the addition of small voltage assistance.