Wireless passive surface acoustic wave vibration sensor

Abstract

The invention provides a wireless passive surface acoustic wave vibration sensor. The wireless passive surface acoustic wave vibration sensor includes an antenna, a matching circuit, a piezoelectric cantilever beam, an SAW device with a reflective delay line structure, a mass oscillator and a cantilever beam fixing pedestal, wherein the SAW device is deposited on the piezoelectric cantilever beam through a semiconductor technology; the mass oscillator and the cantilever beam fixing pedestal are arranged at the tail end of a free end of the cantilever beam; an interdigital energy transducer and two reflectors form the SAW device; buffer materials are respectively arranged at the locations, being opposite to a packaging tube base and a packaging tube cap, on the tail end of the free end of the piezoelectric cantilever beam; when the sensor senses vibration, the mass oscillator at the free end of the piezoelectric cantilever beam enables the piezoelectric cantilever beam to generate one displacement in the force applying direction and generate curved deformation under the effect of acceleration of vibration; and the change of strain on the surface of the piezoelectric cantilever beam causes change of the SAW velocity of propagation in the reflective delay line SAW device, so that time delay and phase of the reflective delay line SAW device are changed correspondingly; and then sensing of the vibration quantity can be realized through decoupling of the sensing information.

Description

technical field [0001] The invention relates to a surface acoustic wave sensor in acoustic technology, in particular to a surface acoustic wave sensor applied to measure vibration. Background technique [0002] Mechanical vibration is a source of information for the diagnosis and monitoring of the internal structure of various machines as well as peripheral protection. Vibration-based detection can judge the technical conditions, design and production quality, and reliability of machinery. Mechanical equipment will vibrate during operation. Vibration exceeding the normal range will increase mechanical fatigue, affect the life of parts, and even cause parts to break and equipment to be damaged. Therefore, detecting the vibration of key mechanical components can effectively monitor the poor state of the equipment, maintain it in time, and play a role in discovering and dealing with problems in advance, which is of great significance for safe production, prolonging the ser...

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Problems solved by technology

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