Capacitance pressure sensor with high Q value and large relative variable quantity

Abstract

The invention discloses a capacitance pressure sensor which is used for wireless and passive measurement. A capacitor is composed of an elastic vibrating diaphragm of which the periphery is fixedly supported; by means of adjusting the ratio of the radium of a circular electrode to the radius of the vibrating diagram and arranging insulated salient points and the like, the vibrating diagram is in a large strain state; and the ratio of the maximum capacitance to the initial capacitance is as big as possible so as to obtain the capacitance with high Q value and large relative variable quantity. After being connected with a surface acoustic wave transmitter, the capacitance pressure sensor with high Q value and large relative variable quantity can realize wireless and passive high-precise measurement on pressure and can be used for the monitoring field of automobile tyre pressure.

Description

Technical field: [0001] The invention belongs to the technical field of pressure monitoring, and in particular relates to a pressure sensor suitable for passive wireless sensing, especially a capacitive pressure sensor with variable pole distance. technical background: [0002] Sensors that work in a passive wireless manner are suitable for harsh working environments, such as high temperature, heavy pollution, strong interference, etc., as well as various physical, chemical or biological conditions that are not suitable for wiring and battery-provided energy on rotating and moving objects Quantity measurement. There are mainly two types of sensors working in a passive wireless manner in the prior art: LC resonance type and SAW (surface acoustic wave) type. The former generally adopts a capacitive sensor, takes the resonant frequency as the measurement quantity, and realizes energy and information transmission by inductive coupling, and adapts to a shorter working distance. ...

AI Technical Summary

Problems solved by technology

[0007] The above-mentioned patent documents cover the electrode with an insulating material layer to solve the problem of electrode short circuit, but it also produces the problem that the deformation of the vibrating membrane is reduced under the action of external pressure, that is, the existence of the insulating layer increases the thickness of the vibrating membrane, Reduce deformation under the same external force

[0008] In addition, none of the above-mentioned patent documents pay attention to the relative change of capacitance and the problem of Q value.

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