CN115102517A - Acoustic surface wave resonator - Google Patents
Acoustic surface wave resonator Download PDFInfo
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- CN115102517A CN115102517A CN202210527406.XA CN202210527406A CN115102517A CN 115102517 A CN115102517 A CN 115102517A CN 202210527406 A CN202210527406 A CN 202210527406A CN 115102517 A CN115102517 A CN 115102517A
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- dielectric material
- embedded dielectric
- interdigital transducer
- 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
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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
- H03H9/02818—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 materials, interdigital transducers, and embedded dielectric materials; 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 fingers of the interdigital transducer, and the width of the embedded dielectric material is the same as the gap between the two adjacent electrode fingers of the interdigital transducer; the invention solves the problem of Rayleigh wave interference, improves the pass band flatness and the out-of-band rejection capability of the filter, and has better comprehensive filtering performance. Meanwhile, the method is easy to realize in the aspect of process, can be popularized in any frequency band, and is high in 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. With the rapid growth of mobile communications, surface acoustic wave filters have been widely used in mobile communication devices. There is an increasing demand for broadband low loss filters for various radio frequency front end systems.
Generally, a broadband low-loss surface acoustic wave filter uses lithium niobate as a piezoelectric substrate. However, the surface acoustic wave resonator of the conventional lithium niobate substrate has serious rayleigh spurious waves near the resonance point and the anti-resonance point, and the rayleigh spurious waves can seriously affect the flatness of the pass band of the filter, so that the filter can form fluctuation more than 5dB in the pass band, and the practical use of the filter is influenced.
The surface acoustic wave filter is designed and manufactured by surface acoustic wave resonators, so that a surface acoustic wave resonator which can restrain rayleigh waves near a passband and can improve flatness of the passband of the filter and out-of-band rejection capability is urgently needed.
Disclosure of Invention
Aiming at 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 invention has the beneficial effects that: the surface acoustic wave resonator provided by the invention can inhibit Rayleigh waves near a passband by periodically arranging the embedded dielectric material; compared with the conventional surface acoustic wave resonator, the invention solves the problem of Rayleigh wave interference, improves the flatness of the pass band of the filter and the out-of-band rejection capability, and has better comprehensive filtering performance. Meanwhile, the method is easy to realize in the aspect of process, can be popularized in any frequency band, and is high in practicability.
Drawings
FIG. 1 is a schematic cross-sectional view of a SAW resonator structure according to the present invention;
FIG. 2 is a top view of a SAW resonator structure of the present invention;
FIG. 3 is a flow chart of the fabrication of the SAW resonator of 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 of the admittance response of a SAW filter designed from the SAW resonator structure 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 designed from the SAW resonator structure of the present invention;
in the figure: 101. a piezoelectric material; 102. an interdigital transducer; 103. an embedded dielectric material.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The present invention proposes a surface acoustic wave resonator, as shown in fig. 1 and 2, the resonator comprising: piezoelectric material 101, interdigital transducer 102, and 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.
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 present 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 a of the interdigital transducer is 2 μm, and the period b of the embedded dielectric material is 4 μm. The ratio h2/h1 of the thickness h2 of the embedded dielectric material to the electrode thickness h1 of the interdigital transducer is 1.5, wherein the thickness h2 of the embedded dielectric material is 0.36 μm, and the electrode thickness h1 of the interdigital transducer is 0.24 μm.
As shown in fig. 3, the production of the surface acoustic wave resonator according to the present invention includes the following steps:
s1: obtaining a piezoelectric substrate (piezoelectric material);
s2: manufacturing a dielectric material layer on a piezoelectric substrate;
s3: coating photoresist on the dielectric material layer, carrying out exposure development, carrying out high-temperature curing on the photoresist after the exposure development, and carrying out etching treatment on the dielectric material layer;
s4: and evaporating a metal film on the etched dielectric material layer to manufacture the interdigital transducer and the metal electrode.
The present 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, an 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, occurs, and the problem of rayleigh wave interference is overcome.
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, there are significant rayleigh waves in the pass band and outside the near-end band of the filter, which cause 5dB performance deterioration to the pass band, and 20dB performance deterioration outside the near-end band, which cannot meet practical requirements; 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, rayleigh waves in the filter passband and outside the near-end band are significantly suppressed, and the flatness of the filter passband and the out-of-band suppression capability are improved.
The surface acoustic wave resonator provided by the invention can inhibit Rayleigh waves near a passband by periodically arranging the embedded dielectric material; compared with the conventional surface acoustic wave resonator, the invention solves the problem of Rayleigh wave interference, improves the flatness of the pass band of the filter and the out-of-band rejection capability, and has better comprehensive filtering performance. Meanwhile, the method is easy to realize in the aspect of process, can be popularized in any frequency band, and is high in practicability.
The above-mentioned embodiments, which are further described in detail for the purpose of illustrating the invention, should be understood that the above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
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), and the embedded dielectric material (103) is periodically distributed between two adjacent electrode fingers of the interdigital transducer.
2. A surface acoustic wave resonator as claimed in claim 1, characterized in that the width of the embedded dielectric material (103) is the same as the gap between two adjacent electrode fingers of the interdigital transducer (102).
3. A surface acoustic wave resonator as claimed in claim 1, characterized in that 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.
4. A surface acoustic wave resonator as claimed in claim 1, characterized in that the thickness h2 of the embedded dielectric material (103) is greater than or equal to the electrode thickness h1 of the interdigital transducer (102).
5. A surface acoustic wave resonator as set forth in claim 1, wherein the piezoelectric material (101) is lithium niobate or a lithium niobate thin film composite material.
6. A surface acoustic wave resonator as claimed in 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 |
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| 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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| CN115102517A true CN115102517A (en) | 2022-09-23 |
| CN115102517B CN115102517B (en) | 2023-10-03 |
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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 |
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- 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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| CN115102517B (en) | 2023-10-03 |
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