Frequency Tunable Ultrasonic Sensor Array Based on Helmholtz Resonant Cavity

Abstract

The invention relates to a frequency-adjustable ultrasonic sensor array based on a Helmholtz resonant cavity. The frequency-adjustable ultrasonic sensor array comprises a base material, an ultrasonictransmitting device and an acoustic wave receiving device, wherein the ultrasonic transmitting device and the acoustic wave receiving device are arranged on the base material, and the acoustic wave receiving device comprises an acoustic sensor and the Helmholtz resonant cavity formed in the acoustic sensor. According to the frequency-adjustable ultrasonic sensor array based on the Helmholtz resonant cavity, the ultrasonic transmitting device and the acoustic wave receiving device are arranged on the same wafer, the resonance frequency of the acoustic sensor in the ultrasonic transmitting device and the resonance frequency of the Helmholtz resonant cavity in the acoustic wave receiving device are consistent, the resonance frequency of an acoustic sensor in the acoustic wave receiving deviceis higher than or lower than the resonance frequency of the acoustic sensor in the ultrasonic transmitting device and the resonance frequency of the Helmholtz resonant cavity in the acoustic wave receiving device, and therefore, crosstalk between array units can be avoided.

Description

technical field [0001] The invention relates to the technical field of sensors, in particular to a frequency-tunable ultrasonic sensor array based on a Helmholtz resonant cavity. Background technique [0002] An ultrasonic transducer is a transducer element that can be used to both transmit and receive ultrasonic waves, and is the core of an acoustic sensor. When working in the transmitting mode, the electric energy is converted into the vibration of the transducer through electrostatic force or inverse piezoelectric effect to radiate sound waves; when working in the receiving mode, the sound pressure acts on the surface of the transducer to vibrate, and the transducer The vibration is then converted into an electrical signal. At present, the most widely used ultrasonic sensors are mainly based on bulk piezoelectric transducers, which mainly use the thickness vibration mode of piezoelectric ceramics to generate ultrasonic waves. Since the resonance frequency of the thicknes...

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Problems solved by technology

At present, there is a serious crosstalk problem in the sensor array. Because the resonant frequencies of the sensors at the transmitting end and the receiving end are similar, the receiving end will inevitably generate interference electrical signals when transmitting ultrasonic waves, which will affect the performance of the sensor array. In addition, each sensor in the array All array elements work at the same operating frequency, their bandwidth is relatively narrow, and the sensitivity of the sensor array needs to be improved

[0005] In general, the receiving unit of the sensor array has disadvantages such as low sensitivity, low acoustic-electric energy conversion efficiency, and unadjustable frequency, and the sensor array has limitations such as severe crosstalk and narrow bandwidth.

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