CN203278768U

Movatterモバイル変換

Info

Publication number: CN203278768U
Application number: CN 201320307230
Authority: CN
Inventors: 李强; 黄铁辉
Original assignee: Zhongke Micro Sound (tianjin) Sensor Technology Co Ltd
Current assignee: Suzhou Guangsheng Nanotechnology Co ltd
Priority date: 2013-05-31
Filing date: 2013-05-31
Publication date: 2013-11-06
Anticipated expiration: 2023-05-31

Abstract

The utility model provides a surface acoustic wave (SAW) resonator with metal lattice and a weighted grid array. The SAW resonator comprises a piezoelectric substrate; a metal interdigital transducer and a metal grid array are sputtered on the substrate; the metal grid array comprises reflection grids arranged on left and right sides of the metal interdigital transducer; reflection grids on the left side are called the first reflection grids, reflection grids on the right side are called the second reflection grids, and the first reflection grids and the second reflection grids are symmetrically distributed on the left and the right sides of the metal interdigital transducer; and both the first reflection grids and the second reflection grids comprise a plurality of grid strips, and the metal lattice is arranged between adjacent grid strips of the first reflection grids and the second reflection grids to weight the reflection grid array. According to the utility model, effects of a high-order transverse wave mode on frequency characteristics of the resonator are avoided, and frequency response performance of the SAW resonator is enhanced.

Description

The SAW (Surface Acoustic Wave) resonator of metal lattice weighting grating array

Technical field

The utility model relates to a kind of SAW (Surface Acoustic Wave) resonator that can eliminate the high-order transverse wave Pattern perturbation, to realize optimization frequency response, belongs to the Signal and Information Processing field.

Background technology

Resonator type sound surface wave (SAW) filter because its performance is good, volume is little, cost is low, is easy to the characteristics such as batch production, is widely used in field of telecommunications.

General SAW resonator is at piezoelectric substrate surface sputtering metal interdigital transducers (Interdigital Transducer, IDT) and metal strip.But in the SAW resonator structure, interdigital transducer is time-limited sound aperture, can produce various acoustic wave diffraction effects.

Document " Analysis of general planar waveguides with n segments; " (IEEE Ultrason. Symp., pp.137 – 141,2000.) point out, the SAW (Surface Acoustic Wave) resonator surface can be divided into 3 zones: metallized area, Free Surface zone and grating array.Acoustic velocity between zones of different is different, the particularly periodicity of metal interdigital electrode and metal strip design, cause other transverse sound wave jamming patterns and deposit.Namely except the first-harmonic resonance pattern of carrying main acoustic signals, also there are a series of high-order transverse wave patterns such as a series of bound mode (bound modes), half bound mode (semi-bound modes) and radiation mode (radiation modes).The existence of these high-order transverse wave patterns can reduce Out-of-band rejection, affects the group delay in passband, causes unevenness in passband, worsens the frequency response characteristic of SAW filter.

In order to eliminate the impact of high-order transverse wave pattern, the structural design of several SAW (Surface Acoustic Wave) resonator has appearred.

(1) document " GHz SAW resonators " (IEEE Ultrason. Symp., pp. 815 – 823,1979) report in, adopt apodization or busbar to adopt the zigzag design, can be used for the spike that level and smooth high-order transverse wave pattern causes, but this can increase device size, and can not eliminate the existence of high-order transverse wave pattern.

(2) document " Low resistance quartz resonators for automotive applications without spurious modes " (IEEE Ultrason. Symp., pp. 1326 – 1329,2004.) report, adopt the first asymmetric first-harmonic pattern in rank to carry acoustic signals, suppress the impact of high-order transverse wave pattern in can the certain frequency scope, but the method only limits to the fewer situation of high-order transverse wave pattern, and can cause certain frequency shift (FS).

Therefore, there is defective in prior art, needs further improvement and develops.

Summary of the invention

For the deficiency that prior art exists, the purpose of this utility model is to provide a kind of SAW (Surface Acoustic Wave) resonator of eliminating the high-order transverse wave Pattern perturbation.

For achieving the above object, technical solution of the present utility model is:

The SAW (Surface Acoustic Wave) resonator of metal lattice weighting grating array, comprise piezoelectric substrate, splash-proofing sputtering metal interdigital transducer and metal strip on described piezoelectric substrate, wherein, described metal strip comprises the reflecting grating that is separately positioned on the described metal interdigital transducers left and right sides, the reflecting grating in left side is called the first reflecting grating, the reflecting grating on right side is called the second reflecting grating, the metal strip that described the first reflecting grating and the second reflecting grating form is symmetrical in the described metal interdigital transducers left and right sides; Described the first reflecting grating and the second reflecting grating comprise respectively many fingers, between the adjacent finger of described the first reflecting grating and the second reflecting grating, metal lattice are set.

The SAW (Surface Acoustic Wave) resonator of described metal lattice weighting grating array, wherein, the thickness of described metal interdigital transducers is 1500 dusts, and the metal finger period λ of described metal interdigital transducers is 9.86 microns, and 70 fingers are set, and pore size is 120 λ.

The SAW (Surface Acoustic Wave) resonator of described metal lattice weighting grating array, wherein, described the first reflecting grating and the second reflecting grating are open-circuit gate or short-circuit gate simultaneously.

The SAW (Surface Acoustic Wave) resonator of described metal lattice weighting grating array, wherein, each reflecting grating comprises 138 fingers.

The SAW (Surface Acoustic Wave) resonator of the metal lattice weighting grating array that the utility model provides, the metal interdigital transducers of sputter rule on piezoelectric substrate, and the first open-circuit gate is set on the left of the metal interdigital transducers of described rule, the second open-circuit gate is set on the right side, between the finger of reflecting grating, metal lattice is set, by adjusting the metallization ratio of the number affects reflecting grating of metal dots in metal lattice, to the weighting of pore size between the reflecting grating finger, realize that the reflecting grating finger of each position has different reflectivity; The utility model utilizes metal lattice that reflecting grating is weighted can eliminate the high-order transverse wave pattern to the impact of resonant frequency characteristic, improves the frequency response performance of SAW resonator.

Description of drawings

Fig. 1 is the structural representation of the SAW (Surface Acoustic Wave) resonator of the utility model metal lattice weighting grating array;

Fig. 2 is after the weighting of the utility model metal lattice reflecting grating, the pore size schematic diagram of the finger of reflecting grating;

Fig. 3 is the weighting of the utility model metal lattice reflecting grating and the contrast schematic diagram in not weighting normalization aperture;

Fig. 4 is that the utility model utilizes the dmittance chart of the SAW (Surface Acoustic Wave) resonator that metal lattice is weighted reflecting grating and analog response figure as a result.

Embodiment

Below by drawings and Examples, the technical solution of the utility model is described in further detail.

Generally speaking, the metal lattice of reflecting grating on Y-direction is more, and metallization is than larger, and the aperture of reflecting grating is less.In the present embodiment, by metal lattice is set, realize the Hamming weighting to reflecting grating on reflecting grating, after described reflecting grating weighting, the pore size of the finger of reflecting grating changes schematic diagram as shown in Figure 2; Before and after described reflecting grating weighting, the normalized pore size of reflecting grating changes schematic diagram as shown in Figure 3.

Utilize metal lattice to the SAW (Surface Acoustic Wave) resonator that reflecting grating is weighted according to what the utility model content provided, comprise piezoelectric substrate, splash-proofing sputtering metal interdigital transducer and metal strip on described piezoelectric substrate; And the metal lattice that the pore size between the metal strip finger is weighted.

The described metal lattice that reflecting grating is weighted, each metal dots is between two adjacent fingers of reflecting grating; By adjust the quantity of metal dots on Y-direction, affect the metallization ratio of Y-direction, realize the weighting to pore size between the finger of reflecting grating.

The material of interdigital transducer described in the utility model can be the metals such as aluminium, gold, does not limit here.

Reflecting grating described in the utility model can be the open-circuit gate battle array, and perhaps the short circuit grating array, do not limit here.

Described piezoelectric substrate adopts the quartz material of ST-X.

Piezoelectric substrate material described in the utility model is the various piezoelectrics that design is selected according to practical devices, and such as the tangential quartz material of difference (AT cuts quartz, Y cuts quartz etc.), perhaps lithium niobate, lithium tantalate etc., do not limit here.

The SAW (Surface Acoustic Wave) resonator that the utility model utilizes metal lattice that reflecting grating is weighted, preferably, the thickness of described metal interdigital transducers is 1500 dusts, and the metal finger of metal interdigital transducers is set to 70, and the cycle λ of the metal finger stripe pitch of metal interdigital transducers is 9.86 microns; Pore size between the metal finger of metal interdigital transducers is 120 λ.

The cycle of described the second reflecting grating and the 3rd reflecting grating is similarly λ, and the grating array of preferably opening a way, each reflecting grating comprise 138 fingers.Pore size in reflecting grating between finger by metal lattice is set, changes the metallization ratio on Y-direction on Y-direction, and then controls pore size.

The described metal lattice that utilizes is weighted dmittance chart and the frequency response results figure of the SAW (Surface Acoustic Wave) resonator of one of front and back to reflecting grating, as shown in Figure 4; As can be seen from Figure 4, utilize the design of the SAW (Surface Acoustic Wave) resonator that metal lattice is weighted reflecting grating, can eliminate the outer higher order mode of passband, little on the impact of passband.

The utility model arranges metal lattice, realizes the Hamming weighting to reflecting grating; Concrete weighted type be substrate material, the metal material of interdigital electrode, the thickness that adopts according to SAW (Surface Acoustic Wave) resonator, and the parameters such as cycle of interdigital transducer obtains.

Above content is the explanation to preferred embodiment of the present utility model, can help those skilled in the art to understand more fully the technical solution of the utility model.But these embodiment only illustrate, and can not assert that embodiment of the present utility model only limits to the explanation of these embodiment.Concerning the utility model person of an ordinary skill in the technical field, without departing from the concept of the premise utility, can also make some simple deductions and conversion, all should be considered as belonging to protection range of the present utility model.

Claims

2. the SAW (Surface Acoustic Wave) resonator of metal lattice weighting grating array according to claim 1, it is characterized in that, the thickness of described metal interdigital transducers is 1500 dusts, and the metal finger period λ of described metal interdigital transducers is 9.86 microns, 70 fingers are set, and pore size is 120 λ.

3. the SAW (Surface Acoustic Wave) resonator of metal lattice weighting grating array according to claim 2, is characterized in that, described the first reflecting grating and the second reflecting grating are open-circuit gate or short circuit grating array simultaneously.

4. the SAW (Surface Acoustic Wave) resonator of metal lattice weighting grating array according to claim 3, is characterized in that, each reflecting grating comprises 138 fingers.