CN115102517B - Surface acoustic wave resonator - Google Patents
Surface acoustic wave resonator Download PDFInfo
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- CN115102517B CN115102517B CN202210527406.XA CN202210527406A CN115102517B CN 115102517 B CN115102517 B CN 115102517B CN 202210527406 A CN202210527406 A CN 202210527406A CN 115102517 B CN115102517 B CN 115102517B
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- dielectric material
- interdigital transducer
- embedded dielectric
- surface acoustic
- acoustic wave
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02543—Characteristics of substrate, e.g. cutting angles
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02637—Details concerning reflective or coupling arrays
- H03H9/02685—Grating lines having particular arrangements
- H03H9/02724—Comb like grating lines
- H03H9/02732—Bilateral comb like grating lines
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02818—Means for compensation or elimination of undesirable effects
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
The invention belongs to the technical field of filters, and particularly relates to a surface acoustic wave resonator; the resonator includes: piezoelectric material, interdigital transducer, and embedded dielectric material; the interdigital transducer and the embedded dielectric material are both arranged on the piezoelectric material, the embedded dielectric material is periodically distributed between two adjacent electrode finger strips of the interdigital transducer, and the width of the embedded dielectric material is the same as the gap between the two adjacent electrode finger strips of the interdigital transducer; the method solves the Rayleigh wave interference problem, improves the pass band flatness and the out-of-band rejection capability of the filter, and has better comprehensive filtering performance. Meanwhile, the invention is easy to realize in the process aspect, can be popularized in any frequency band, and has high practicability.
Description
Technical Field
The invention belongs to the technical field of filters, and particularly relates to a surface acoustic wave resonator.
Background
The surface acoustic wave filter has the advantages of small volume, light weight, good consistency and the like. Along with the rapid growth of mobile communication, the surface acoustic wave filter has been widely used in mobile communication devices. Various radio frequency front-end systems are increasingly in demand for broadband low-loss filters.
Typically, a wideband low-loss surface acoustic wave filter employs lithium niobate as a piezoelectric substrate. However, the conventional surface acoustic wave resonator with the lithium niobate substrate has serious rayleigh wave parasitics near the resonance point and the antiresonance point, and the rayleigh wave parasitics can seriously influence the flatness of the passband of the filter, so that the filter can form fluctuation of more than 5dB in the passband, and the actual use of the filter is influenced.
The surface acoustic wave filter is designed and manufactured by a surface acoustic wave resonator, and therefore, there is a need for a surface acoustic wave resonator capable of suppressing rayleigh waves near the passband and improving the flatness of the passband and the out-of-band suppression capability of the filter.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a surface acoustic wave resonator, which comprises: a piezoelectric material (101), an interdigital transducer (102) and an embedded dielectric material (103); the interdigital transducer (102) and the embedded dielectric material (103) are both arranged on the piezoelectric material (101), and the embedded dielectric material (103) is periodically distributed between two adjacent electrode fingers of the interdigital transducer.
Preferably, the width of the embedded dielectric material (103) is the same as the gap between two adjacent electrode fingers of the interdigital transducer (102).
Preferably, the ratio of the period b of the embedded dielectric material (103) to the half period a of the interdigital transducer (102) is an integer greater than or equal to 2.
Preferably, the thickness h2 of the embedded dielectric material (103) is greater than or equal to the electrode thickness h1 of the interdigital transducer (102).
Preferably, the piezoelectric material (101) is lithium niobate or a lithium niobate thin film composite material.
Preferably, the embedded dielectric material (103) is silicon dioxide or silicon nitride.
The beneficial effects of the invention are as follows: according to the surface acoustic wave resonator provided by the invention, the Rayleigh waves near the passband can be restrained by periodically arranging the embedded dielectric material; compared with the conventional surface acoustic wave resonator, the invention solves the Rayleigh wave interference problem, improves the pass band flatness and out-of-band rejection capability of the filter, and has better comprehensive filtering performance. Meanwhile, the invention is easy to realize in the process aspect, can be popularized in any frequency band, and has high practicability.
Drawings
FIG. 1 is a schematic cross-sectional view of a SAW resonator of the present invention;
FIG. 2 is a top view of a SAW resonator structure in accordance with the present invention;
FIG. 3 is a flow chart of a surface acoustic wave resonator according to the present invention;
FIG. 4 is a graph of the admittance response of a SAW filter designed from a conventional SAW resonator structure;
FIG. 5 is a graph showing the admittance response of a SAW filter constructed from the SAW resonator of the present invention;
FIG. 6 is a graph of the frequency response of a SAW filter designed from a conventional SAW resonator structure;
FIG. 7 is a graph showing the frequency response of a SAW filter constructed from the SAW resonator of the present invention;
in the figure: 101. a piezoelectric material; 102. an interdigital transducer; 103. an embedded dielectric material.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a surface acoustic wave resonator, as shown in fig. 1 and 2, comprising: a piezoelectric material 101, an interdigital transducer 102, and an embedded dielectric material 103; both the interdigital transducer 102 and the embedded dielectric material 103 are disposed on the piezoelectric material 101, the embedded dielectric material 103 being periodically distributed between two adjacent electrode fingers of the interdigital transducer.
The width of the embedded dielectric material 103 is the same as the gap between two adjacent electrode fingers of the interdigital transducer 102.
The ratio of the period b of the embedded dielectric material 103 to the half period a of the interdigital transducer 102 is an integer greater than 2.
The thickness h2 of the embedded dielectric material 103 is greater than or equal to the electrode thickness h1 of the interdigital transducer 102.
The piezoelectric material 101 is lithium niobate or a lithium niobate thin film composite material.
The embedded dielectric material 103 is silicon dioxide or silicon nitride.
In some embodiments of the invention, the piezoelectric material is lithium niobate and the dielectric material is silicon dioxide. The ratio of the period b of the embedded dielectric material to the half period a of the interdigital transducer is 2, i.e. the period b of the embedded dielectric material is 2 times the half period a of the interdigital transducer, wherein the half period of the interdigital transducer is a=2 μm and the period of the embedded dielectric material is b=4 μm. The ratio h 2/h1=1.5 of the thickness h2 of the embedded dielectric material to the electrode thickness h1 of the interdigital transducer, wherein the thickness h2=0.36 μm of the embedded dielectric material and the electrode thickness h1=0.24 μm of the interdigital transducer.
As shown in fig. 3, the fabrication of the surface acoustic wave resonator according to the present invention includes the following steps:
s1: acquiring a piezoelectric substrate (piezoelectric material);
s2: manufacturing a dielectric material layer on a piezoelectric substrate;
s3: coating photoresist on the dielectric material layer, exposing and developing, curing the photoresist after exposing and developing at high temperature, and etching the dielectric material layer;
s4: evaporating a metal film on the etched dielectric material layer to manufacture the interdigital transducer and the metal electrode.
The invention was evaluated:
compared with the conventional surface acoustic wave resonator, as shown in fig. 4, in the admittance response curve of the surface acoustic wave filter designed by the conventional surface acoustic wave resonator structure, obvious clutter is arranged on the left side of a resonance point, and the clutter is Rayleigh waves; as shown in fig. 5, in the admittance response curve of the surface acoustic wave filter designed by the surface acoustic wave resonator structure of the present invention, no clutter, i.e. no rayleigh wave, appears, thus overcoming the problem of rayleigh wave interference.
As shown in fig. 6, in the frequency response curve of the surface acoustic wave filter designed by the conventional surface acoustic wave resonator structure, obvious rayleigh waves exist in the passband of the filter and outside the near-end band, 5dB performance degradation is caused to the passband, 20dB performance degradation exists outside the near-end band, and practical requirements cannot be met; as shown in fig. 7, in the frequency response curve of the surface acoustic wave filter designed by the surface acoustic wave resonator structure of the present invention, the rayleigh waves in the passband and the near-end out-of-band of the filter are obviously suppressed, and the flatness of the passband and the out-of-band suppression capability of the filter are improved.
According to the surface acoustic wave resonator provided by the invention, the Rayleigh waves near the passband can be restrained by periodically arranging the embedded dielectric material; compared with the conventional surface acoustic wave resonator, the invention solves the Rayleigh wave interference problem, improves the pass band flatness and out-of-band rejection capability of the filter, and has better comprehensive filtering performance. Meanwhile, the invention is easy to realize in the process aspect, can be popularized in any frequency band, and has high practicability.
While the foregoing is directed to embodiments, aspects and advantages of the present invention, other and further details of the invention may be had by the foregoing description, it will be understood that the foregoing embodiments are merely exemplary of the invention, and that any changes, substitutions, alterations, etc. which may be made herein without departing from the spirit and principles of the invention.
Claims (3)
1. A surface acoustic wave resonator, comprising: a piezoelectric material (101), an interdigital transducer (102) and an embedded dielectric material (103); the interdigital transducer (102) and the embedded dielectric material (103) are both arranged on the piezoelectric material (101), the embedded dielectric material (103) is periodically distributed between two adjacent electrode fingers of the interdigital transducer, the embedded dielectric material (103) and the air gap are alternately distributed between two adjacent electrode fingers of the interdigital transducer (102), the embedded dielectric material (103) does not cover between adjacent electrode fingers of all interdigital transducers (102), and the gaps between adjacent electrode fingers of the interdigital transducer (102) between the adjacent embedded dielectric materials (103) are not provided with the embedded dielectric material (103); the ratio of the period b of the embedded dielectric material (103) to the half period a of the interdigital transducer (102) is an integer greater than or equal to 2; the thickness h2 of the embedded dielectric material (103) is greater than or equal to the electrode thickness h1 of the interdigital transducer (102); the width of the embedded dielectric material (103) is the same as the gap between two adjacent electrode fingers of the interdigital transducer (102).
2. A surface acoustic wave resonator according to claim 1, characterized in that the piezoelectric material (101) is lithium niobate or a lithium niobate thin film composite.
3. A surface acoustic wave resonator according to claim 1, characterized in that the embedded dielectric material (103) is silicon dioxide or silicon nitride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210527406.XA CN115102517B (en) | 2022-05-16 | 2022-05-16 | Surface acoustic wave resonator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210527406.XA CN115102517B (en) | 2022-05-16 | 2022-05-16 | Surface acoustic wave resonator |
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| Publication Number | Publication Date |
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| CN115102517A CN115102517A (en) | 2022-09-23 |
| CN115102517B true CN115102517B (en) | 2023-10-03 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202210527406.XA Active CN115102517B (en) | 2022-05-16 | 2022-05-16 | Surface acoustic wave resonator |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110601674A (en) * | 2019-09-27 | 2019-12-20 | 中国科学院上海微系统与信息技术研究所 | High-frequency acoustic wave resonator and preparation method thereof |
| CN111010126A (en) * | 2019-12-12 | 2020-04-14 | 无锡市好达电子有限公司 | Surface acoustic wave filter structure of layered electrode and preparation method thereof |
| CN112803911A (en) * | 2021-01-05 | 2021-05-14 | 无锡市好达电子股份有限公司 | Preparation method of surface acoustic wave transducer with temperature compensation function |
| CN113541637A (en) * | 2021-08-25 | 2021-10-22 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator, preparation method thereof and surface acoustic wave filter |
| CN113794458A (en) * | 2021-09-16 | 2021-12-14 | 无锡市好达电子股份有限公司 | Surface acoustic wave device with composite film layer |
-
2022
- 2022-05-16 CN CN202210527406.XA patent/CN115102517B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110601674A (en) * | 2019-09-27 | 2019-12-20 | 中国科学院上海微系统与信息技术研究所 | High-frequency acoustic wave resonator and preparation method thereof |
| CN111010126A (en) * | 2019-12-12 | 2020-04-14 | 无锡市好达电子有限公司 | Surface acoustic wave filter structure of layered electrode and preparation method thereof |
| CN112803911A (en) * | 2021-01-05 | 2021-05-14 | 无锡市好达电子股份有限公司 | Preparation method of surface acoustic wave transducer with temperature compensation function |
| CN113541637A (en) * | 2021-08-25 | 2021-10-22 | 江苏卓胜微电子股份有限公司 | Surface acoustic wave resonator, preparation method thereof and surface acoustic wave filter |
| CN113794458A (en) * | 2021-09-16 | 2021-12-14 | 无锡市好达电子股份有限公司 | Surface acoustic wave device with composite film layer |
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| Publication number | Publication date |
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| CN115102517A (en) | 2022-09-23 |
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Effective date of registration: 20230908 Address after: 200030 No. 1954, Huashan Road, Shanghai, Xuhui District Applicant after: SHANGHAI JIAO TONG University Applicant after: CHINA ELECTRONICS TECHNOLOGY GROUP CORPORATION NO.26 Research Institute Address before: 400060 No. 14, Huayuan Road, Nan'an District, Chongqing Applicant before: CHINA ELECTRONICS TECHNOLOGY GROUP CORPORATION NO.26 Research Institute |
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