CN100514854C - Acoustic surface-wave oscillator system for gas sensor - Google Patents
Acoustic surface-wave oscillator system for gas sensor Download PDFInfo
- Publication number
- CN100514854C CN100514854C CNB2004100034786A CN200410003478A CN100514854C CN 100514854 C CN100514854 C CN 100514854C CN B2004100034786 A CNB2004100034786 A CN B2004100034786A CN 200410003478 A CN200410003478 A CN 200410003478A CN 100514854 C CN100514854 C CN 100514854C
- Authority
- CN
- China
- Prior art keywords
- saw
- acoustic wave
- surface acoustic
- delay line
- oscillator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Oscillators With Electromechanical Resonators (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
- Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
Abstract
The disclosed system comprises two groups of acoustic surface wave oscillator composed of acoustic surface wave delay line, radio frequency amplifier and phasing network, and one group of mixer circuit composed of mixer, low frequency amplifier and low pass filter. Outputs of two groups of oscillator are connected to the mixer. The output of the mixer passing through low pass filter and low frequency amplifier outputs signal of difference frequency between two groups of oscillator. Two groups of delay line are fabricated on same substrate. Single-phase unidirectional transducer (SPUDT) structure is adopted in delay line so as to reduce insertion loss. Length of the long transducer is equal to distance between geometric centers of transducers. Comb structure is adopted, and gap between combs is equal to length of the short transducer in order to restrain unwanted mode of oscillation. The oscillator is operated at single mode so as to raise frequency stability (0.07 ppm).
Description
Technical field
The present invention relates to a kind of oscillator, particularly relate to a kind of surface acoustic wave (" SAW ") oscilator system that is used for gas sensor.
Background technology
As everyone knows, for the gas sensor core component be the oscillator of high frequency high stability.Usually so in actual applications high stability oscillator roughly has two kinds, a kind of is crystal oscillator, but studies show that, square being bordering on of the sensitivity of transducer and frequency of oscillation is directly proportional, and the frequency of oscillation of crystal oscillator generally is not more than 30MHz, therefore, crystal oscillator can not be applicable to the more gas sensor of high sensitivity requirement.Another is a SAW (Surface Acoustic Wave) oscillator, this oscillator has higher frequency stability, on the operating frequency this SAW device than crystal oscillator height two orders of magnitude, therefore adopt the gas sensor of this SAW (Surface Acoustic Wave) oscillator also just to have the ability of the bigger sensitivity of acquisition.This SAW (Surface Acoustic Wave) oscillator generally has two types, and a kind of is to adopt both-end resonator type sound surface wave oscillator, and its frequency stability is very high, and the gas sensor of this resonator type has very high sensitivity, and resolution can reach 10 usually
-12To 10
-15But provide the carrier area of the needed sensitive membrane of gas sensor very little generally speaking, this in addition resonator type oscillator is made quite complicated, and be subjected to the influence of circuit phase state easily and cause the unsteadiness of transducer, therefore this oscillator generally is not suitable for gas sensor.Another is the SAW (Surface Acoustic Wave) oscillator that adopts the SAW (Surface Acoustic Wave) delay line type, it can provide the needed carrier of gas sensor sensitive membrane of enough areas, also has simultaneously very high frequency stability, be not easy to be subjected to the influence of peripheral circuit phase place, therefore this oscillator is more suitable for the use in gas sensor.
The delay line type SAW (Surface Acoustic Wave) oscillator system that is applied to gas sensor of prior art generally adopts conventional two delay line type oscillator structures, usually the delay-line structure that is adopted does not have the control of single-frequency oscillatory work pattern, and the loss of delay line is quite big.In the middle of prior art, general delay line adopts the transducer of two equal length, and its length all within 50 to 100 wave-length coverages, is inserted loss between 20 to 60 dB, and the amplifier that therefore must adopt high-gain compensates the loss of delay line.Wohltijen in 1979 propose surface acoustic wave sensor (the H.Wohltjen andR.E.Dessy of this employing delay-line structure at first, " Surface acoustic wave probe for chemical analysis; PartsI-III ", Analytical Chem., vol.5, no.9, pp.1458-1475,1979), in the middle of his design of 34MHz SAW (Surface Acoustic Wave) delay line, the substrate that is adopted is the ST quartz, delay line adopts two identical transducers, and its periodicity is 8, and sound aperture is 26.5 times of wavelength, distance is 460 times of wavelength between two transducers, and the loss of delay line surpasses 60dB.Wohltijen in 1986 to 1987 etc. have proposed three kinds of SAW (Surface Acoustic Wave) oscillator (David S.Ballantine that are applied to gas sensor again, Susan L.Rose, Jay W.Grateand H.Wohltjen, " Correlation of Surface Acoustic Wave Device CoatingResponses with Solubility Properties and Chemical Structure Using PatternRecognition ", Anal.Chem., vol.58, no.14, December, pp.3058-3066,1986H.Wohltjen, W.Snow, R.Barger and David S.Ballantine, " Trace ChemicalVapor Detecion Using SAW Delay Line Oscillators ", 1987 IEEEUFFC, vol.UFFC-34, no.2, MARCH, pp.172-178).Adopt 31MHz respectively, 52MHz and 112MHzSAW delay line.Three kinds of delay lines all adopt same transducer to refer to logarithm (be 50 refer to), sound aperture is 80 times of wavelength, finger beam and refer to that a spacing is 1/4 wavelength, and the transducer spacing is respectively 264 times, 166 times and 350 times of wavelength, substrate is the ST quartz, and these three kinds of delay line losses are all greater than 20dB.People such as Jay W.Grate in 1988 and Arthur Snow propose the delay line type oscillator that is applied to gas sensor (the Jay W.Grate of a kind of 158MHz, Arthur Snow, David S.Ballantine, H.Wohltjen, " Determination of Partition Coefficients from Surface Acoustic WaveVapor Sensor Responses and Correlation with Gas-Liquid CheomatographicPartition Coefficients ", Anal.Chem., vol.60, no9, May1, pp.869-875,1988), input transducer length is that 75 fingers are right, output transducer is that 100 fingers are right, the transducer spacing is 10 wavelength, and sound aperture is 70 wavelength, and adopting substrate is the ST quartz.There are some to adopt the delay-line structure of lithium niobate substrate in addition.A kind of gas sensor (Liu Guofeng as designs such as Liu Guofeng, Chen Ming; " novel sonic surface wave gas sensors "; aviation instrumentation technology, the 15th volume, the third phase; pp.5-8; 1995) to adopt the delay line centre frequency of lithium niobate substrate be 60MHz, and each IDT 30 refers to rightly, and distance is 60 times of wavelength between 2 IDT.External also have some to adopt vibration type sonic surface wave gas sensors (Yuan Xiaoping, " external surface acoustic wave sensor exploitation recent developments ", piezoelectricity and acousto-optic, 17th volume, 4th phase, pp.6-10,1995 Rohs, the Y.R. of YZ lithium niobate as substrate; Kim, H.B.; Lee, Y.J.; Cho, H.M.; Chung, J.S.; Baik, S., " Development of SAW gas sensor for monitoringSO
XGas ", Ultrasonics Symposium, 1995.Proceedings., 1995 IEEE, Volume:1,7-10 Nov.1995 Pages:473-476 vol.1).All there are following some shortcomings in the SAW (Surface Acoustic Wave) oscillator that more than is applied to gas sensor:
1. SAW (Surface Acoustic Wave) delay line itself can not solve the pattern control problem of SAW (Surface Acoustic Wave) oscillator, can only rely on external circuit to solve, will inevitably make the circuit complexity like this, strengthen the power consumption of system, influence the structural compactness and the temperature stability of sensing system.
2. what existing sonic surface wave gas sensors adopted is the delay line of substrate with the quartz, normally adopts conventional singly referring to or two finger structure, causes loss too high (usually greater than 20dB); Therefore oscillating circuit adopts the radio frequency amplifier of high-gain to come element loss in compensating device and the circuit with regard to requiring.Adopt the amplifier of high-gain will improve the power consumption of whole system, and will directly have influence on the short-term frequency stability of oscillator, thereby will have influence on the stability and the sensitivity of gas sensor.
3. in addition for the delay-line structure that adopts lithium niobate substrate,, be that the delay line of substrate can obtain lower insertion loss therefore with this material because this substrate has superior electromechanical coupling factor.But this substrate temperature stability is very poor, with producing serious temperature drift, influences the frequency stability of SAW (Surface Acoustic Wave) oscillator, and then has influence on the sensitivity of gas sensor.And in the sonic surface wave gas sensors that adopts this substrate is used, must have constant temperature and humidity conditioner usually, and so clearly increased the burden of electronic circuit, do not meet the miniaturization of gas sensor, portable requirement.
Summary of the invention
The objective of the invention is to: overcome existing deficiency in above-mentioned traditional sonic surface wave gas sensors; Thereby provide a kind of low insertion loss that has, single-mode control, the SAW (Surface Acoustic Wave) delay line type oscilator system that is applied to sonic surface wave gas sensors of good temperature characterisitic; And this SAW (Surface Acoustic Wave) oscillator system uses element amount few, and circuit is simple, and is low in energy consumption, and is easy to operate and have a good frequency stability.
The object of the present invention is achieved like this:
The SAW (Surface Acoustic Wave) oscillator system that is used for gas sensor provided by the invention, comprise two groups of SAW (Surface Acoustic Wave) oscillator and one group of mixting circuits of forming by frequency mixer 5, low frequency amplifier 6 and low pass filter 4 of forming by SAW (Surface Acoustic Wave) delay line 1, radio frequency amplifier 3, phase-shift network 2; It is characterized in that: described SAW (Surface Acoustic Wave) delay line 1 is made up of SAW (Surface Acoustic Wave) device and matching network 25; Wherein said SAW (Surface Acoustic Wave) device is for being provided with two first interdigital transducers 7 different in size and second interdigital transducer 8 on a substrate 10 upper edge sonic propagation directions, and the reflecting electrode 22 that one first interdigital transducer 7 is set, with the reflecting electrode 22 ' that one second interdigital transducer 8 is set, described first interdigital transducer 7 and second interdigital transducer adopt the SPUDT structure; Between first interdigital transducer 7 and second interdigital transducer 8, be provided with a golden film 9; Described first interdigital transducer 7 is the comb transducer structure, and the equal in length of the interval between the broach and second interdigital transducer 8, the distance between first interdigital transducer 7 and second interdigital transducer, 8 centers equals the length of first interdigital transducer 7 simultaneously;
The output of described SAW (Surface Acoustic Wave) delay line 1 is directly received phase-shift network 2 and is carried out the oscillation starting points phase adjusted, make the minimal losses place of oscillation starting points corresponding to SAW (Surface Acoustic Wave) delay line 1, output with phase-shift network 2 inserts radio frequency amplifier 3 then, directly feeds back to the input of SAW (Surface Acoustic Wave) delay line 1 through the output of amplifying back radio frequency amplifier 3; The output of two groups of SAW (Surface Acoustic Wave) oscillator inserts frequency mixer 5, after the output of frequency mixer 5 is filtered the interference of high-frequency signal through a low pass filter 4, by the difference frequency signal of two groups of oscillators of low frequency amplifier 6 back outputs;
Described matching network 25 is made up of series connection coupling inductance L 1 series connection coupling inductance L 2 and coupling inductance L 3 in parallel, coupling inductance L 4 in parallel; It is linked to each other with network analyzer output M1 with coupling inductance L 2 in parallel via the coupling of the series connection in the matching network 25 inductance L 1 by SAW (Surface Acoustic Wave) device input N1, and the output N2 of SAW (Surface Acoustic Wave) device links to each other with network analyzer input M2 with coupling inductance L 4 in parallel via the coupling of the series connection in the matching network 25 inductance L 3 and forms.
Described two groups of SAW (Surface Acoustic Wave) delay line 1 are arranged on the same substrate 10, with the influence of maximum elimination peripheral environment along the acoustic surface wave propagation direction.Described SAW (Surface Acoustic Wave) delay line 1 adopts the single phase unidirectional transducer structure, and the forward of wherein arbitrary single-phase transducer radiative acoustic wave points to another single phase unidirectional transducer; The interdigital transducer 7 of described SAW (Surface Acoustic Wave) delay line 1 and 8 interdigital electrode width are 1/8th wavelength, and reflecting electrode 22 and 22 ' width are quarter-wave; Reflecting electrode 22 in the delay line bar fork finger transducer 7 is positioned at the right left side of interdigital electrode, and the reflecting electrode 22 ' in the short interdigital transducer 8 of delay line is positioned at the right the right of interdigital electrode.
In technique scheme, described SAW (Surface Acoustic Wave) delay line 1 is to adopt the single phase unidirectional transducer (representing with SPUDT) and the single mode control structure of gold electrode, as shown in Figure 2, wherein SAW (Surface Acoustic Wave) delay line 1 is by a bar fork finger transducer 7 and a short interdigital transducer 8, and the distance between two transducers equals the length of bar fork finger transducer, also is provided with the carrier of one deck gold film 9 as the gas sensor sensitive membrane between two transducers; Wherein golden membrane area is generally at 3-5mm
2, be preferably 4mm
2About.Wherein bar fork finger transducer 7 adopts pectinate texture, and interval between the broach and short interdigital transducer 8 equal in length of delay line.The single phase single direction structure of the gold electrode of this SAW (Surface Acoustic Wave) delay line 1, different with the single phase single direction structure of the general aluminium electrode of using always, because the phase place of the reflection coefficient of gold electrode is just in time opposite with the aluminium electrode, gold electrode is corrosion-resistant more than the aluminium electrode in addition, therefore is more suitable for the application in gas sensor.
In technique scheme, also comprise the matching network of a SAW (Surface Acoustic Wave) delay line, as shown in Figure 3, this matching network is imported series inductance 11 and shunt inductance 12 in the M1 circuit by the input N1 and the network analyzer of SAW (Surface Acoustic Wave) delay line; Series inductance 13 and shunt inductance 14 in the output N2 of SAW (Surface Acoustic Wave) delay line and the network analyzer output M2 circuit, M1 and M2 are connected to form with output with the network analyzer input respectively.Make this SAW (Surface Acoustic Wave) delay line reach the optimum Match state by this matching network, and then realize least gain and optimum angle state.
In technique scheme, described phase-shift network 2 comprises: electric capacity 18,20 and 21 and controllable impedance 19 form, with reference to the part of marking 2 among the figure 5, wherein, the input K1 of phase-shift network 2 connects the output of SAW (Surface Acoustic Wave) delay line, and the output K2 of phase-shift network 2 connects the input of radio frequency amplifier 3.An electric capacity 18 in parallel controllable impedance 19 of connecting again earlier between the input K1 of phase-shift network 2 and the K2, the electric capacity 21 of connecting again behind the electric capacity 20 in parallel then.By regulating controllable impedance 19, can change the oscillation starting points phase place flexibly, make the lowest loss place of oscillation starting points phase place, to improve the frequency stability of oscillator corresponding to delay line.
In technique scheme, described radio frequency amplifier 3 comprises input K3 and output K4 and two earth terminal K5 and K6, the input K4 of radio frequency amplifier 3 is electrically connected with the output K2 of phase-shift network 2, such as among Fig. 5 shown in the part of mark 3, and the output K4 of radio frequency amplifier directly feeds back to the input port N1 of SAW (Surface Acoustic Wave) delay line 1.Radio frequency amplifier 3 must satisfy the gain requirement, be that Amplifier Gain must can compensate SAW (Surface Acoustic Wave) delay line and circuit loss, in order to guarantee that oscillator has good frequency stability, radio frequency amplifier should have lower noise factor (representing with NF) simultaneously.This radio frequency amplifier have low-noise factor NF be about 3.50 and low gain G be 16 characteristics.
The invention has the advantages that: SAW (Surface Acoustic Wave) delay line among the present invention is owing to used single phase unidirectional transducer and the single mode control structure that adopts gold electrode, reduce device and inserted loss, make that simultaneously oscillator is operated in single-frequency, solve the problem that prior art exists.The present invention adopts a phase-shift network with controllable impedance to regulate the oscillation starting points phase place in addition, makes the lowest loss place of the oscillation starting points of oscillator corresponding to delay line, has so just improved the frequency stability of SAW (Surface Acoustic Wave) oscillator.The present invention has also added the matching network of SAW (Surface Acoustic Wave) delay line, makes this SAW (Surface Acoustic Wave) delay line reach the optimum Match state by this matching network, and then realizes least gain and optimum angle state.Because the loss of SAW (Surface Acoustic Wave) delay line is low, so the radio frequency amplifier that is adopted among the present invention has the characteristics of low gain and low-noise factor, reduced the power consumption of system, improved the frequency stability of SAW (Surface Acoustic Wave) oscillator.The frequency stability of SAW (Surface Acoustic Wave) oscillator can reach 0.07ppm in the present invention.
Description of drawings
Fig. 1 is the structural representation that is applied to the SAW (Surface Acoustic Wave) oscillator system of gas sensor of the present invention;
Fig. 2 is the structural representation of the present invention program's SAW (Surface Acoustic Wave) delay line
Fig. 3 is the matching network schematic diagram of the present invention program's SAW (Surface Acoustic Wave) delay line;
Fig. 4 is a planimetric sketch of showing the SAW delay line of a conventional SPUDT type;
Fig. 5 is the present invention program's phase-shift network and amplifier circuit figure;
Fig. 6 is the typical amplitude-frequency response figure of SAW (Surface Acoustic Wave) delay line of the present invention (SAW delay line as shown in Figure 2);
Fig. 7 is the typical phase response curve figure of SAW (Surface Acoustic Wave) delay line of the present invention (SAW delay line as shown in Figure 2);
Drawing is described as follows:
1. SAW (Surface Acoustic Wave) delay line 2. phase-shift networks 3. radio frequency amplifiers
4. low pass filter 5. frequency mixers 6. low frequency amplifiers
7. SAW (Surface Acoustic Wave) delay line bar fork finger transducer 8. SAW (Surface Acoustic Wave) delay line are lacked interdigital transducer
9. golden film 10. substrates 11. series connection coupling inductance L 1
12. coupling inductance L 3 13. series connection coupling inductance L 2 14. coupling inductance L 4 in parallel in parallel
15. SAW (Surface Acoustic Wave) delay line 16. substrates of conventional SPUDT structure
17. the input interdigital transducer of the delay line of conventional SPUDT structure
18. phase-shift network shunt capacitance C1 19. phase-shift networks series connection controllable impedance L5
20. phase-shift network shunt capacitance C2 21. phase-shift network series capacitance C3
22. golden reflecting electrode 23. aluminium reflection electrodes
24. the output interdigital transducer of the delay line of conventional SPUDT structure
25. matching network N1. represents the input of SAW (Surface Acoustic Wave) delay line
N2. the output N3. that represents SAW (Surface Acoustic Wave) delay line represents golden film earth point
M1. network analyzer input M2. network analyzer output
K1. the output of the input K2. phase-shift network of phase-shift network
K3. the output of the input K4. radio frequency amplifier of radio frequency amplifier
K5. the ground connection of the ground connection K6. radio frequency amplifier of radio frequency amplifier
Embodiment
In order more fully to understand the present invention, and, can consult following detailed description of the present invention in conjunction with respective drawings now for understanding additional objects and advantages of this invention.
With reference to figure 1, making one is applied to the SAW (Surface Acoustic Wave) oscillator system of gas sensor, this oscilator system is made up of conventional frequency mixer 5, one conventional low frequency amplifier 6 of two groups of SAW (Surface Acoustic Wave) oscillator and a group and general low pass filter 4 as seen from Figure 1, and each organizes SAW (Surface Acoustic Wave) oscillator then by one group of SAW (Surface Acoustic Wave) delay line 1, conventional radio frequency amplifier 3, phase-shift network 2 with constitute.Delay line 1 is as the feedback element of whole oscillator.Two groups of delay lines are produced on the same substrate.By the workflow of the present invention program's the SAW (Surface Acoustic Wave) oscillator that is applied to gas sensor as can be seen among Fig. 1.For each group oscillator, the output N2 of delay line 1 inserts the input K1 of phase-shift network 2, regulate oscillator oscillation starting points phase place by phase-shift network, make oscillation starting points corresponding to SAW (Surface Acoustic Wave) delay line 1 minimal losses place, the output K2 of phase-shift network 2 inserts the input K3 of radio frequency amplifier 3 then, and the output K4 of radio frequency amplifier 3 feeds back to the input N1 of SAW (Surface Acoustic Wave) delay line 1, wherein radio frequency amplifier 3 must satisfy the gain requirement of SAW (Surface Acoustic Wave) oscillator, that is to say that the gain of radio frequency amplifier must be able to compensate the loss and the interlock circuit loss of SAW (Surface Acoustic Wave) delay line, has so just realized the work of this group oscillator.The output of two-way oscillator is connected to frequency mixer 5, by a low pass filter 4, amplifies the difference frequency signal that output obtains final needed two-way oscillator by a low frequency amplifier 6 again after filtering the interference of high-frequency signal after the mixing.
Referring to accompanying drawing 2, this illustrates SAW (Surface Acoustic Wave) delay line 1 structure according to present embodiment, this SAW (Surface Acoustic Wave) delay line 1 adopts single phase unidirectional transducer (SPUDT) structure (can adopt the reflecting grating weighting as required, to improve amplitude-frequency and phase-frequency response) and single mode comb transducer structure.Wherein bar fork finger transducer 7 is to adopt four groups of electrode structures, and each group electrode refers to constitute by 20 pairs of electrodes and 60 pairs of vacations.Short interdigital transducer 8 adopts 80 pairs of electrodes.Electrode is a gold.22 and 22 ' is reflecting electrode.Sound aperture is 100 times of wavelength.Distance is 150 times of wavelength between the transducer 7 and 8, two transducer geometric center distances equal the length of transducer 1 like this to guarantee the single-mode control of oscillator, sufficiently long acoustic path length also is provided in addition, guarantee high Q (quality factor) value of delay line, thereby improved the short-term frequency stability of SAW (Surface Acoustic Wave) oscillator.This SPUDT structure and single mode structure have guaranteed the low-loss of delay line, and low energy reaches 8 dB, and can guarantee that SAW (Surface Acoustic Wave) oscillator is operated in the SAW (Surface Acoustic Wave) delay line under the single-mode.
Described interdigital transducer adopts the SPUDT structure; Be provided with a golden film 9 between bar fork finger transducer 7 and short interdigital transducer 8, golden film 9 is the sensitive membrane carriers that are used for gas sensor, and area is at 3-5mm
2Described bar fork finger transducer 7 is the comb transducer structure, and the equal in length of the short interdigital transducer 8 of the interval between the broach and delay line, simultaneously bar fork finger transducer 7 with lack distance between interdigital transducer 8 centers and equal the length of bar fork finger transducer 7;
The delay line of the SAW (Surface Acoustic Wave) delay line 1 of the embodiment of the invention adopts the ST quartz, two groups of SAW (Surface Acoustic Wave) delay line 1 are made in a ST quartz substrate 10 and (rotate 42.75 ° of Y cuttings, the ST quartz substrate that directions X is propagated) on, adopt this substrate to guarantee the temperature characterisitic that oscillator is good.N1 and N2 represent the input and the output of SAW (Surface Acoustic Wave) delay line respectively, and N3 is golden film earth point.This SAW (Surface Acoustic Wave) delay line and conventional delay line (referring to Fig. 4) difference are: the SAW (Surface Acoustic Wave) delay line of conventional SPUDT structure adopts the aluminium electrode structure, and the SAW (Surface Acoustic Wave) delay line among the present invention program is to adopt the gold electrode structure, the reflection coefficient phase of gold electrode is just in time opposite with the aluminium electrode, thereby cause the complete difference of two kinds of structures, the reflecting electrode 22 of delay line bar fork finger transducer 7 is positioned at interdigital to the left side among Fig. 2, the reflecting electrode 22 ' of short interdigital transducer 8 is positioned at interdigital to the right, and among Fig. 4 reflecting electrode 23 positions of input interdigital transducer 17 interdigital to the right, the reflecting electrode 23 ' of output interdigital transducer 24 interdigital to the left side.The present invention program adopts a major reason of gold electrode to be because the corrosion resistance of gold is much better than the aluminium electrode in addition, is more suitable for the application in gas sensor.
Fig. 3 is the matching network of this SAW (Surface Acoustic Wave) delay line.This matching network is by series inductance 11 and shunt inductance 12 in the input N1 of SAW (Surface Acoustic Wave) delay line and the network analyzer input M1 circuit; Series inductance 13 and shunt inductance 14 in the output N2 of SAW (Surface Acoustic Wave) delay line and the network analyzer output M2 circuit, M1 and M2 are connected to form with output with the network analyzer input respectively.Make this SAW (Surface Acoustic Wave) delay line reach the optimum Match state by this matching network, and then realize least gain and optimum angle state.
Referring to Fig. 4, what have the SPUDT structure is the SAW (Surface Acoustic Wave) delay line 15 of electrode with aluminium for common, by two isometric interdigital transducers with single phase single direction structure 17 and 24 and substrate 16 form.As can be seen from the figure, the position of reflecting electrode is just in time opposite with the SAW (Surface Acoustic Wave) delay line that the employing gold among the present invention is made electrode, this is because reflection coefficient phase and the aluminium of gold just in time opposite, this SPUDT structure is because adopting aluminium is electrode, is subjected to the corrosion of the gas of surveying easily and is not suitable for the application of gas sensor.
Fig. 5 shows according to the present invention program's phase-shift network 2 and radio frequency amplifier 3 circuit diagrams.This circuit comprises a phase-shift network 2 and a radio frequency amplifier 3.As seen from Figure 1, the output K2 of phase-shift network 2 inserts the input K3 of radio frequency amplifier 3, and the output K4 of radio frequency amplifier 3 feeds back to the input of SAW delay line 1.And the output N2 of SAW delay line 1 is connected to the input K1 of phase-shift network.Owing to adopted low-loss SAW (Surface Acoustic Wave) delay line structure, therefore can use the amplifier of low gain, and then improve the frequency stability of SAW (Surface Acoustic Wave) oscillator, reduce power consumption, simplify circuit.As Fig. 5 radio frequency amplifier 3 of the present invention, comprise input K3 and output K4 and earth terminal K5 and K6, have lower noise factor (NF is about 3.50), gain lower (G is 16).In addition, for SAW (Surface Acoustic Wave) oscillator, generally adopt phased approach, adopt phase-shift network control oscillation starting points phase place.Phase-shift network 2 as shown in Figure 5 is by shunt capacitance 18,20 and series capacitance 21 and series connection controllable impedance 19 compositions.Element that network uses is simple.Adopt controllable impedance 19 can obtain phase shift leading or that lag behind flexibly, according to State Control oscillation starting points phase place after the coupling of SAW (Surface Acoustic Wave) delay line, reduce the influence particularly influence of the phase place of SAW (Surface Acoustic Wave) delay line of peripheral environment, stablize starting of oscillation at the centre frequency place of SAW (Surface Acoustic Wave) delay line to guarantee oscillator for the oscilator system phase place.According to the present invention program, SAW (Surface Acoustic Wave) oscillator is tested measured frequency stability and is reached 0.07ppm.
Fig. 6 and Fig. 7 show the typical amplitude-frequency response (inserting the about 9dB of loss) and the phase response of observed SAW delay line 1 from network analyzer respectively, from Fig. 6 and Fig. 7 as can be seen, phase place is along with frequency linearity changes in the passband, make frequency of oscillation near centre frequency by adjusting phase-shift network, when phase change 2 π, frequency drops on outside the amplitude-frequency response passband, and inserting loss increases more than the 10dB, do not satisfy the amplitude starting condition for oscillation, can't starting of oscillation.From Fig. 6 and Fig. 7, in passband, have only a pattern starting of oscillation in addition as can be seen, realized the single mode operation of SAW (Surface Acoustic Wave) oscillator.
Claims (5)
1. SAW (Surface Acoustic Wave) oscillator system that is used for gas sensor, comprise two groups of SAW (Surface Acoustic Wave) oscillator and one group of mixting circuits of forming by frequency mixer (5), low frequency amplifier (6) and low pass filter (4) of forming by SAW (Surface Acoustic Wave) delay line (1), radio frequency amplifier (3), phase-shift network (2); It is characterized in that: described SAW (Surface Acoustic Wave) delay line (1) is made up of SAW (Surface Acoustic Wave) device and matching network (25); Wherein, two groups of SAW (Surface Acoustic Wave) delay line (1) are produced on the same substrate; Described SAW (Surface Acoustic Wave) device is for being provided with two first interdigital transducers (7) different in size and second interdigital transducer (8) on the sonic propagation direction of described substrate (10) upper edge, and the reflecting electrode (22) that one first interdigital transducer (7) is set, with the reflecting electrode (22 ') that one second interdigital transducer (8) is set, described first interdigital transducer (7) and second interdigital transducer (8) adopt the SPUDT structure; Between first interdigital transducer (7) and second interdigital transducer (8), be provided with a golden film (9); Described first interdigital transducer (7) is the comb transducer structure, and the equal in length of the interval between the broach and second interdigital transducer (8), the distance between first interdigital transducer (7) and second interdigital transducer (8) center equals the length of first interdigital transducer (7) simultaneously;
The output of described SAW (Surface Acoustic Wave) delay line (1) is directly received phase-shift network (2) and is carried out the oscillation starting points phase adjusted, make the minimal losses place of oscillation starting points corresponding to SAW (Surface Acoustic Wave) delay line (1), output with phase-shift network (2) inserts radio frequency amplifier (3) then, directly feeds back to the input of SAW (Surface Acoustic Wave) delay line (1) through the output of amplifying back radio frequency amplifier (3); The output of two groups of SAW (Surface Acoustic Wave) oscillator inserts frequency mixer (5), after the output of frequency mixer (5) is filtered the interference of high-frequency signal through a low pass filter (4), by the difference frequency signal of two groups of oscillators of low frequency amplifier (6) back output;
Described matching network (25) is made up of series connection coupling inductance L 1 (11), series connection coupling inductance L 2 (13) and coupling inductance L 3 (12) in parallel, coupling inductance L 4 (14) in parallel; It is linked to each other with network analyzer output M1 with coupling inductance L 2 (12) in parallel via the coupling of the series connection in the matching network (25) inductance L 1 (11) by SAW (Surface Acoustic Wave) device input N1, and the output N2 of SAW (Surface Acoustic Wave) device links to each other with network analyzer input M2 with coupling inductance L 4 (14) in parallel via the coupling of the series connection in the matching network (25) inductance L 3 (13) and forms.
2. the SAW (Surface Acoustic Wave) oscillator system that is used for gas sensor according to claim 1, it is characterized in that: described SAW (Surface Acoustic Wave) delay line (1) is to have single phase single direction structure, and what also have the single mode control structure simultaneously is the SAW (Surface Acoustic Wave) delay line of electrode with the gold.
3. the SAW (Surface Acoustic Wave) oscillator system that is used for gas sensor according to claim 1 is characterized in that: described golden film (9) area is at 3-5mm
2
The 4 SAW (Surface Acoustic Wave) oscillator systems that are used for gas sensor according to claim 1 is characterized in that: described substrate (10) is 42.75 ° of Y cuttings of rotation, and directions X is propagated the ST quartz substrate.
5. the SAW (Surface Acoustic Wave) oscillator system that is used for gas sensor according to claim 1, it is characterized in that: described phase-shift network (2) comprising: at input (K1) electric capacity in parallel successively (18) of phase-shift network, the controllable impedance (19) of connecting, an electric capacity (20) in parallel, the electric capacity (21) of connecting links to each other with output (K2) then.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100034786A CN100514854C (en) | 2004-03-30 | 2004-03-30 | Acoustic surface-wave oscillator system for gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100034786A CN100514854C (en) | 2004-03-30 | 2004-03-30 | Acoustic surface-wave oscillator system for gas sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1677853A CN1677853A (en) | 2005-10-05 |
| CN100514854C true CN100514854C (en) | 2009-07-15 |
Family
ID=35050198
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100034786A Expired - Fee Related CN100514854C (en) | 2004-03-30 | 2004-03-30 | Acoustic surface-wave oscillator system for gas sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100514854C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101865884A (en) * | 2009-11-24 | 2010-10-20 | 中国科学院声学研究所 | Single-mode protruding double-end resonant surface acoustic wave detector |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100058834A1 (en) * | 2008-09-09 | 2010-03-11 | Honeywell International Inc. | Method and apparatus for low drift chemical sensor array |
| CN103066943B (en) * | 2012-12-21 | 2015-09-09 | 中国科学院声学研究所 | A kind of SAW (Surface Acoustic Wave) resonator for gas sensor |
| CN103066945B (en) * | 2012-12-21 | 2015-11-04 | 中国科学院声学研究所 | For the SAW mode of resonance oscilator system of gas sensor |
| CN105227138B (en) * | 2015-09-11 | 2019-01-22 | 中国科学院声学研究所 | A kind of radio frequency circuit system |
| CN106788427A (en) * | 2016-11-30 | 2017-05-31 | 北京无线电计量测试研究所 | One kind imprisons radio frequency source for mercury ion Microwave Frequency target |
| CN106911990A (en) * | 2017-03-09 | 2017-06-30 | 歌尔股份有限公司 | MEMS sonic transducers and its manufacture method |
| CN107015048B (en) * | 2017-04-21 | 2019-08-30 | 中国科学院声学研究所 | A kind of surface acoustic wave current sensor based on magnetostrictive effect |
| CN108933579B (en) * | 2018-06-22 | 2020-11-06 | 中国科学院声学研究所 | Acoustic surface wave single-end-to-resonator |
| CN111189911B (en) * | 2020-01-10 | 2022-07-15 | 西安科技大学 | Mine safety monitoring system design method based on surface acoustic wave sensor |
| CN111781270B (en) * | 2020-07-06 | 2022-02-22 | 中国科学院声学研究所 | Differential phase discrimination circuit system for surface acoustic wave gas sensor |
| CN114050842B (en) * | 2022-01-12 | 2022-05-03 | 南通大学 | Radio frequency transceiving system for offshore wind power level measurement and working method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4100811A (en) * | 1977-03-18 | 1978-07-18 | United Technologies Corporation | Differential surface acoustic wave transducer |
| US6314791B1 (en) * | 1997-10-20 | 2001-11-13 | Forschungszentrum Karlsruhe Gmbh | Surface acoustic wave sensor |
-
2004
- 2004-03-30 CN CNB2004100034786A patent/CN100514854C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4100811A (en) * | 1977-03-18 | 1978-07-18 | United Technologies Corporation | Differential surface acoustic wave transducer |
| US6314791B1 (en) * | 1997-10-20 | 2001-11-13 | Forschungszentrum Karlsruhe Gmbh | Surface acoustic wave sensor |
Non-Patent Citations (4)
| Title |
|---|
| Fabrication of a thick film sensor employing anultrasonicoscillator. N.M.White,G.R.Leach.Science,Measurement and Technology,IEE Proceedings,Vol.142 No.3. 1995 |
| Fabrication of a thick film sensor employing anultrasonicoscillator. N.M.White,G.R.Leach.Science,Measurement and Technology,IEE Proceedings,Vol.142 No.3. 1995 * |
| 声表面波压力传感器的研制. 张晖，程国辉，李国选.压电与声光，第11卷第6期. 1989 |
| 声表面波压力传感器的研制. 张晖，程国辉，李国选.压电与声光，第11卷第6期. 1989 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101865884A (en) * | 2009-11-24 | 2010-10-20 | 中国科学院声学研究所 | Single-mode protruding double-end resonant surface acoustic wave detector |
| CN101865884B (en) * | 2009-11-24 | 2012-08-15 | 中国科学院声学研究所 | Single-mode protruding double-end resonant surface acoustic wave detector |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1677853A (en) | 2005-10-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN100514854C (en) | Acoustic surface-wave oscillator system for gas sensor | |
| CN102197591B (en) | Surface acoustic wave resonator, surface acoustic wave oscillator, and surface acoustic wave module device | |
| US7579928B2 (en) | Surface acoustic wave device and communication device | |
| EP1251638B1 (en) | Surface acoustic wave filter apparatus and communications apparatus | |
| EP0545672B1 (en) | Low loss wide bandwidth parallel channel acoustic filter | |
| US6366002B1 (en) | Surface acoustic wave device and communication device | |
| KR100494049B1 (en) | Surface acoustic wave filter and communication apparatus | |
| CN103066945B (en) | For the SAW mode of resonance oscilator system of gas sensor | |
| JP4541853B2 (en) | Antenna duplexer and surface acoustic wave filter for antenna duplexer | |
| CN105427570A (en) | Passive and wireless telemetering interface chip for general reactance-type sensing element | |
| JP3269466B2 (en) | Surface wave resonator, surface wave filter, duplexer, communication device | |
| KR100588450B1 (en) | Surface acoustic wave element and portable telephone set using the same | |
| US6806619B2 (en) | Interdigital transducer, surface acoustic wave filter, and radio communication apparatus | |
| US6469598B2 (en) | SAW filter with unidirectional transducer and communication apparatus using the same | |
| CN100571026C (en) | SAW (Surface Acoustic Wave) delay line with single phase single direction structure | |
| CN2689592Y (en) | Sound surface wave delaying lines | |
| JPH09135142A (en) | Surface acoustic wave converter and surface acoustic wave filter using the converter | |
| JP3387028B2 (en) | Surface acoustic wave device | |
| US20030067246A1 (en) | Unidirectional surface acoustic wave transducer | |
| Li et al. | Optimal design of an RSPUDT-based SAW filter with constant group delay | |
| Cordoves et al. | Double Transit Echo Suppression of Surface Acoustic Waves in a Passive Wireless Reflective Delay-Line Device Employing a 3 rd Harmonic Optimized Single Phase Transducer and a Tunable Antenna | |
| JP2002111431A (en) | Elastic surface wave apparatus | |
| JPH0319505A (en) | Surface acoustic wave oscillation circuit | |
| JPH03112210A (en) | Surface acoustic wave device | |
| Solal et al. | A new low impedance balanced drive structure for SAW transversely coupled resonator filters |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090715 Termination date: 20110330 |