A wireless passive surface acoustic wave strain sensor

Abstract

The invention relates to a wireless passive surface acoustic wave strain sensor comprising a surface acoustic wave reflective delay line device, a first matching network, a second matching network, a reference strain gauge and a perception strain gauge, wherein the surface acoustic wave reflective delay line device as a responder of a wireless sensing system employs a binary channel reflector type structure. A reference channel is connected to the reference strain gauge through the first matching network. A sensing channel is connected to the perception strain gauge through the second matching network. The wireless passive surface acoustic wave strain sensor of the invention adopts the external strain gauge to sense the strain capacity in a loaded mode so as to solve the problem of force temperature coupling caused by the direct strain of the surface acoustic wave device, and is more stable and reliable than the direct measurement of the strain with the surface acoustic wave device. In addition, the surface acoustic wave reflection type delay line device uses the binary channel reflector type structure to solve the temperature disturbance problem in the strain measurement process by a differential method.

Description

technical field [0001] The invention relates to a surface acoustic wave sensor in acoustic technology, in particular to a wireless passive surface acoustic wave sensor applied to measuring strain. Background technique [0002] As a key component of industrial process control, strain sensors are widely used in aerospace, petroleum and petrochemical, electric power, motor vehicles, and railways. For example, a real-time monitoring application of the health of a helicopter wing operation. [0003] Traditional strain sensors are generally based on the resistive strain effect. The principle is that when a metal conductor or semiconductor is subjected to an external force, the corresponding strain will cause its resistance value to change accordingly. This type of strain sensor is widely used, but there are some problems that need to be solved urgently: resistive strain sensor has low resistance sensitivity, so it is necessary to use a bridge to amplify the signal, resulting in ...

AI Technical Summary

Problems solved by technology

This type of strain sensor is widely used, but there are some problems to be solved urgently: the resistive strain sensor has low resistance sensitivity, so it is necessary to use a bridge to amplify the signal, resulting in complicated circuits; second, the resistive strain sensor has low resolution, The dynamic response is poor, and the change of resistance value is greatly affected by temperature; third, the strain sensor adopts the battery-powered active detection method, which is difficult to adapt to extreme environments such as high temperature, high pressure and unattended

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