CN102435344A - Surface acoustic wave temperature sensor - Google Patents

Abstract

The invention provides a surface acoustic wave temperature sensor which comprises a circuit board and a substrate, wherein an antenna device for receiving and transmitting signals is arranged on the circuit board, and a resonant cavity for providing resonant signals and two reflection grids for absorbing reflection signals are arranged on the substrate. According to the surface acoustic wave temperature sensor, the resonant signal is provided through the resonant cavity on the substrate, high-end transverse mode response is inhibited, and the reflection signal is absorbed through the reflection grid electrode, so that low-end parasitic response is inhibited; and the corresponding surface acoustic wave temperature sensor only consists of a circuit board and a substrate, so that the volume of the device is reduced, and the application of the surface acoustic wave device can realize miniaturization.

Description

A kind of surface acoustic wave temperature sensor

Technical field

The invention provides a kind of surface acoustic wave temperature sensor that is applied to the temperature early warning type of intelligent grid, belong to the temperature measurement technology field.

Background technology

In today of sensor technology fast development, for the special occasions of many sensor application, the line between sensor and unit under test normally can't be realized.For example, when carrying out the parameter measurement of slip-ring brush, rotor and many moving objects, can produce a lot of mechanical problems and circuit problem, interruption, noise can occur, even can't measure at all with the line sensor.For another example, the measurement of acceleration in car during car crass, the measurements of doughnut internal pressure, temperature and friction etc. also are the modes that can not adopt line.Therefore, must adopt wireless senser to realize measuring to these special occasions.

Wireless senser can be divided into two kinds by the energy-provision way difference: active and passive sensor.The test that active sensor is applied to above-mentioned special occasions be have a lot of circumscribed.Directly supply power and passive sensor need not power supply, it keeps working sensor by electromagnetic energy.In existing wireless sensor technology; Because measurement parameter is to gather and transmit through wireless sensing; The interference that inevitably exists high-end transverse mode response low side spurious response to cause, and the volume of sensor is all bigger, be unfavorable for measurement space than hour application.

Summary of the invention

The objective of the invention is n-butene to be converted into isobutylene through fixed-bed catalytic isomery method; Adopt the weldering plate type heat exchanger simultaneously; And, solve the too high problem of reaction product temperature, and then a kind of n-butene fixed-bed catalytic isomery method is provided through degree of depth heat transfer technology.

The objective of the invention is to realize through following technical scheme:

A kind of surface acoustic wave temperature sensor; Comprise circuit board and substrate; Said circuit board is provided with and supplies signal to receive and the antenna transmission device, and said substrate is provided with the resonator cavity and two the reflection grids that are used to absorb reflected signal that are used to provide resonance signal.

Technical scheme by the invention described above provides can be found out; Surface acoustic wave temperature sensor of the present invention provides resonance signal through on-chip resonator cavity, has suppressed high-end transverse mode response; Absorb reflected signal through the reflection grid, suppressed low side spurious response; And corresponding surface acoustic wave temperature sensor only is made up of circuit board and substrate two parts, has reduced device volume, makes sound table device application can realize miniaturization.

Description of drawings

Fig. 1 is the structural representation of the surface acoustic wave temperature sensor that provides of the specific embodiment of the invention.

Embodiment

The specific embodiment of the invention provides a kind of surface acoustic wave temperature sensor; As shown in Figure 1;Comprise circuit board 1 andsubstrate 2;Circuit board 1 is provided with and supplies signal to receive and antenna transmission device 1-1, andsubstrate 2 is provided with the resonator cavity and two the reflection grids that are used to absorb reflected signal that are used to provide resonance signal.

Concrete; Compare with general resonator, the resonator cavity finger of the substrate that this embodiment provides adopts cosine function weighting design, has suppressed high-end transverse mode response; Guaranteed the high-amplitude value of output signal to the full extent, made the realization of signal long-distance transmissions become possibility.In the design of reflection grid, break through conventional finger arrangement mode, adopt the reflecting grating array mode of dot matrix weighting, suppressed low side spurious response, eliminated the influence of noise signal so to greatest extent, guaranteed the high s/n ratio of output signal.Wafer is chosen the quartz crystal that adopts special angle (can select the angle of AT39 °～42 ° of scopes), has guaranteed the high linearity relation of frequency shift (FS) and corresponding temperature.

In the reception and transmission of signal; The sensor that this embodiment provides receives the electromagnetic wave signal that PC is launched through the antenna that is provided with on the circuit board; When the signal that is received identical with self resonance frequency or relatively near the time, the resonating device generation resonance of sensor.Simultaneously owing to receive the Influence of Temperature of the equipment of being guarded; Can the squint centre frequency of device of the frequency of this resonating device; And the antenna through being provided with on the circuit board sends to PC with this frequency signal with form of electromagnetic wave, realizes the real-time monitoring to power equipment.

The temperature that the design concept of the surface acoustic wave temperature sensor that this embodiment provides the is based on sound table material characteristic of wafing, material different have the different temperature coefficient that wafts, and be as shown in the table:

Substrate material	The temperature coefficient (PPM/ ℃) that wafts
		41LN	80
64LN	70
		128LN	75
YZLN	94

Substrate material in the last table and the temperature coefficient that wafts is concrete instance, also can select the wafer of other material as required for use, like the quartz of lithium tantalate, special angle etc.

The frequency of the sensor that this embodiment provides is higher, arrives between the 439M scope at 428M.Because frequency is higher, so the size of chip is less, it is 75% aluminium electrode that dutycycle is taken in the selection of aluminium electrode simultaneously, makes product can realize the encapsulation of miniaturization surface-mount type, and the miniaturization that is suitable for equipment develops.

The surface acoustic wave temperature sensor of the technical scheme that the employing present embodiment provides because on-chip resonator cavity transducer adopts cosine function weighting design, has suppressed high-end transverse mode response; The reflection grid has adopted the dot matrix weighting, has suppressed low side spurious response.Choosing of aluminium electrode, the employing dutycycle is 75% aluminium electrode, has improved reflection, so can guarantee the output amplitude and the signal to noise ratio (S/N ratio) of its signal.On material selection, adopt the crystal of special cut direction, realized that frequency changes with temperature linearity.Because the employing dutycycle is 75% aluminium electrode, reduced device volume simultaneously, made sound table device application can realize miniaturization.

The above; Be merely the preferable embodiment of the present invention, but protection scope of the present invention is not limited thereto, any technician who is familiar with the present technique field is in the technical scope that the present invention discloses; The variation that can expect easily or replacement all should be encompassed within protection scope of the present invention.

Claims (5)

1. surface acoustic wave temperature sensor; Comprise circuit board and substrate; It is characterized in that; Said circuit board is provided with and supplies signal to receive and the antenna transmission device, and said substrate is provided with the resonator cavity and two the reflection grids that are used to absorb reflected signal that are used to provide resonance signal.

2. surface acoustic wave temperature sensor according to claim 1 is characterized in that, said substrate employing dutycycle is 75% aluminium electrode.

3. surface acoustic wave temperature sensor according to claim 1 is characterized in that, said resonator cavity adopts cosine function weighting design to process.

4. surface acoustic wave temperature sensor according to claim 1 is characterized in that, said reflection grid adopts dot matrix weighting design to process.

5. surface acoustic wave temperature sensor according to claim 1 is characterized in that, said resonator cavity adopts the small-sized Surface Mount type encapsulation of 3.8mm * 3.8mm.

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