CN2323515Y - Low-insertion loss IF surface acoustic wave filter for communication - Google Patents
Low-insertion loss IF surface acoustic wave filter for communication Download PDFInfo
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- CN2323515Y CN2323515Y CN 97227680 CN97227680U CN2323515Y CN 2323515 Y CN2323515 Y CN 2323515Y CN 97227680 CN97227680 CN 97227680 CN 97227680 U CN97227680 U CN 97227680U CN 2323515 Y CN2323515 Y CN 2323515Y
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- weighting
- transducer
- digit
- insertion loss
- acoustic wave
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Abstract
The utility model relates to an acoustic surface wave intermediate frequency filter in the applied acoustics. The utility model adopts Y112 DEG LiTao< 3 > as a base sheet, and two interdigital transducers both adopt electrode width controlling single-phase unidirectional transducers. The two transducers can be both provided with digit pumping weighting, or one transducer is provided with digit cutting weighting, and the other transducer is provided with digit pumping weighting, or one transducer is provided with digit cutting weighting, and the other transducer isn't provided with any weighting, or one transducer is provided with digit pumping weighting, and the other transducer isn't provided with any weighting, wherein, the weighting of reflecting gratings totally adopts digit pumping weighting. The strength of reflected signals is controlled by changing the thicknesses of reflecting grating bars to control the insertion loss of the filter. The utility model obtains low insertion loss in relatively large band widths.
Description
The utility model relates to a kind of low Insertion Loss intermediate-frequency filter of surface acoustic wave that is used for radio communication.
The radio communication that prior art exists (comprise mobile phone, cordless telephone and personal communication such as use at system) is with some has adopted low Insertion Loss to design (Insertion Loss is less than 10dB) in the surface acoustic wave intermediate-frequency filter.Other insertion loss is big (more than the 15dB) all, as U.S.'s surface acoustic wave techniques (SAWTEK) company product.And the substrate material that inserts these lower intermediate-frequency filters of loss is quartz, thereby bandwidth less (0.19%-0.78%).
Order of the present utility model cut in proposing a kind of employings X, rotate 112 ° of Y propagation lithium tantalates and (write a Chinese character in simplified form Y112 ° of LiTaO
3) surface acoustic wave intermediate-frequency filter that substrate is formed, it can reduce the insertion loss of filter greatly, thereby reduces the power consumption of system effectively, and guarantees that enough bandwidth are arranged, to satisfy the needs of system.Thereby solved the existing in prior technology problem.
The technical scheme that the utility model adopted is that it includes two control electrode width single phase unidirectional transducers on piezoelectric substrate, and stock is that X cuts, and 112 ° of rotation Y propagate lithium tantalate (LiTaO
3), wherein the intensity of the reflected signal of reflecting grating can be controlled by changing grizzly bar thickness, and piezoelectric substrate is bonded on the base, and inputing or outputing electrode is to be connected with pin by lead-in wire.This piezoelectric substrate adopts Y112 ° of LiTaO
3Material; Two interdigital transducers all adopt control electrode width single phase unidirectional transducer.The transducer weighting can all be a withdraw-weighted, also can be one and cut the finger weighting, and another is a withdraw-weighted; Also can be a not weighting, another be for cutting the finger weighting; Can also be a not weighting, another be a withdraw-weighted.Wherein withdraw-weighted is all adopted in the reflecting grating weighting.Its characteristics are that the reflected signal of reflecting grating mainly comes from the contribution of mechanics load, increase along with the increase of thickness, and the intensity of reflected signal is controlled by changing thickness, thus the insertion loss of control filters.
Advantage of the present utility model is: (1) adopts Y112 ° of LiTaO
3Substrate, electromechanical coupling factor is bigger than quartzy, and bandwidth of operation is quartzy wideer than adopting, and approximately can arrive 1.5%.(2) because the intensity of reflected signal increases with reflection grizzly bar thickness, can reduce Insertion Loss by control reflection grizzly bar thickness, minimum is inserted loss and can be accomplished below the 4dB.
Fig. 1 is the partial cutaway structural representation of the utility model embodiment.
Fig. 3 is the amplitude-frequency response of Fig. 2 embodiment.
Below in conjunction with accompanying drawing the utility model preferred embodiment is further described.
As shown in Figure 1, it is that the intermediate-frequency filter example structure schematic diagram, the Surface Acoustic Wave Filter chip 2 that are used for spread-spectrum (CDMA) wireless communication system are bonded in base 1, inputs or outputs electrode and links to each other with pin 4 by lead-in wire 3.
Fig. 2 is the structural representation of Fig. 1 embodiment chips 2.By Y112 ° of LiTaO
3Two control electrode width single phase unidirectional transducers 6 on the substrate 5 and 7 are formed.Withdraw-weighted is all adopted in the transducing of two transducers and the weighting of reflecting grating array.The width of reflection grizzly bar 8 is λ/4 (λ is the centre frequency wavelength), is spaced apart 3 λ/16 between it and the adjacent finger, other finger width and be λ/8 at interval.The length that suppresses two transducers for the stopband that improves filter is unequal, is respectively 106 λ and 92 λ, and the quantity of reflection grizzly bar is respectively 72 and 62, and thickness is 4000 .
Fig. 3 is the amplitude-frequency response of embodiment among Fig. 2, and as can be seen from the figure, the about 0.8MHz of 1dB bandwidth inserts loss less than 4.5dB, and stopband suppresses less than 45dB.
Claims (3)
1. a surface acoustic wave intermediate-frequency filter is characterized in that it includes two control electrode width single phase unidirectional transducers on piezoelectric substrate, and stock is that X cuts, and 112 ° of rotation Y propagate lithium tantalate (LiTaO
3), wherein the intensity of the reflected signal of reflecting grating can be controlled by changing grizzly bar thickness, and piezoelectric substrate is bonded on the base, and inputing or outputing electrode is to be connected with pin by lead-in wire.
2. according to the said surface acoustic wave intermediate-frequency filter of claim 1, it is characterized in that said two transducers, its transducer weighting can all be to take out finger transducer; Also can be one and cut the finger weighting, another is a withdraw-weighted; Also can be a not weighting, another be to cut the finger weighting; Can also be a not weighting, another be a withdraw-weighted.
3. according to the said surface acoustic wave intermediate-frequency filter of claim 1, it is characterized in that said transducer, its reflection is deleted the weighting of battle array and is adopted withdraw-weighted, and the width that bar is deleted in reflection is λ/4.The intensity of reflected signal is controlled by changing grizzly bar thickness, thus the insertion loss of control filters.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97227680 CN2323515Y (en) | 1997-09-25 | 1997-09-25 | Low-insertion loss IF surface acoustic wave filter for communication |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 97227680 CN2323515Y (en) | 1997-09-25 | 1997-09-25 | Low-insertion loss IF surface acoustic wave filter for communication |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2323515Y true CN2323515Y (en) | 1999-06-09 |
Family
ID=33941009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 97227680 Expired - Fee Related CN2323515Y (en) | 1997-09-25 | 1997-09-25 | Low-insertion loss IF surface acoustic wave filter for communication |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2323515Y (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101091310B (en) * | 2005-10-03 | 2012-06-13 | 株式会社村田制作所 | Elastic wave filter device and duplexer |
-
1997
- 1997-09-25 CN CN 97227680 patent/CN2323515Y/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101091310B (en) * | 2005-10-03 | 2012-06-13 | 株式会社村田制作所 | Elastic wave filter device and duplexer |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |