Surface acoustic wave transducer and device comprising the same
By dividing the interdigitated electrode structure into multiple regions and setting discontinuously weighted traces, the problem of lateral energy leakage in the resonator is solved, achieving better filter performance and cost-effectiveness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- MAXSCEND MICROELECTRONICS CO LTD
- Filing Date
- 2023-05-08
- Publication Date
- 2026-07-21
AI Technical Summary
Existing resonators suffer from lateral energy leakage during sound wave propagation, affecting the steepness of the transition band and the flatness within the passband. Furthermore, existing suppression methods are costly or require larger filters.
In the interdigitated electrode structure, multiple regions are divided. By setting discontinuous weighted first and second traces in the direction of surface acoustic wave propagation, the aperture of the finger strips in the first region is equal, and discontinuous weighting is formed between adjacent regions to suppress transverse modes.
It effectively suppresses transverse energy leakage of acoustic waves, improves the steepness of the transition band and the flatness within the passband of the filter, while reducing manufacturing costs and size requirements.
Smart Images
Figure CN118921035B_ABST
Abstract
Description
Technical Field
[0001] Embodiments of the present invention relate to the semiconductor field, and more particularly to a surface acoustic wave transducer and an apparatus including the same. Background Technology
[0002] With the continuous improvement of mobile communication technology, the number of communication frequency bands has also increased dramatically. The guard interval between frequency bands of different communication systems is becoming smaller and smaller. Currently, the frequency domain characteristics of filters are mainly used to avoid mutual interference between frequency bands. Resonators are important components of filters.
[0003] Figure 1 This is a schematic diagram of the current resonator structure. (Example) Figure 1 As shown, the resonator includes interdigitated electrodes and reflectors 31 located on both sides of the interdigitated electrodes. The interdigitated electrodes include a first busbar 11 and a second busbar 21. Multiple first electrode fingers 12 and multiple first virtual fingers 13 are alternately arranged on the first busbar 11. Multiple second electrode fingers 22 and multiple second virtual fingers 23 are alternately arranged on the second busbar 21. In the direction of surface acoustic wave propagation (i.e., the horizontal direction in the figure), the multiple first electrode fingers 12 and multiple second electrode fingers 22 are staggered. The first electrode fingers 12 and the second virtual fingers 23 are positioned opposite each other with gaps. The second electrode fingers 22 and the first virtual fingers 13 are positioned opposite each other with gaps. The lines connecting the ends of all the first electrode fingers 12 (or the lines connecting the gaps between the ends of all the first electrode fingers 12) and the lines connecting the ends of all the second electrode fingers 22 (or the lines connecting the gaps between the ends of all the second electrode fingers 22) are straight lines along the direction of surface acoustic wave propagation. Figure 1 The resonator shown has a problem of transverse energy leakage of acoustic waves, which will seriously worsen the steepness of the transition band and the flatness in the passband, and introduce stray resonance into the resonator.
[0004] Currently, when suppressing transverse modes, most methods involve adding an extra layer of metal to the finger strip ends of the resonator to reduce the sound velocity in that region. While this method effectively suppresses transverse modes, its effectiveness is highly sensitive to mass load and weight, requiring sophisticated manufacturing processes and increasing costs. Another technique for suppressing transverse modes involves designing the interdigital electrodes with a tilted structure, which increases the area of the interdigital electrodes and is detrimental to reducing filter cost and size. Summary of the Invention
[0005] The present invention is proposed to alleviate or solve at least one of the above-mentioned problems in the prior art.
[0006] According to one aspect of an embodiment of the present invention, a surface acoustic wave transducer is provided, comprising: a piezoelectric layer; interdigitated electrodes disposed on the surface of the piezoelectric layer, including: a first busbar and a plurality of first electrode fingers connected to the first busbar, a second busbar and a plurality of second electrode fingers connected to the second busbar; the interdigitated electrodes include a plurality of regions arranged in the propagation direction of the surface acoustic wave, the plurality of regions including at least adjacent first regions and second regions, a line connecting the ends of the plurality of second electrode fingers in the first region defining a first trace, and a line connecting the ends of the plurality of second electrode fingers in the second region defining a second trace, wherein: adjacent ends of the first trace and the second trace are staggered in the extension direction of the electrode fingers, and the finger strip apertures in the first region are equal.
[0007] According to one aspect of an embodiment of the present invention, an apparatus is provided comprising the surface acoustic wave transducer described above. Attached Figure Description
[0008] The following description and accompanying drawings will better aid in understanding these and other features and advantages of the various embodiments disclosed herein, wherein the same reference numerals in the drawings always denote the same parts, wherein:
[0009] Figure 1 This is a top view schematic diagram of a known resonator;
[0010] Figure 2 This is a top view schematic diagram of a surface acoustic wave transducer according to an exemplary embodiment of the present invention;
[0011] Figure 3 The test results are illustrated in the figure below. Figure 2 Admittance of a medium surface acoustic wave transducer as a function of frequency;
[0012] Figure 4 The chart shows a comparison of the test results, which respectively demonstrate... Figure 1 and Figure 2 Curve showing the real part of the admittance of a surface acoustic wave transducer as a function of frequency;
[0013] Figures 5-9 This is a top view schematic diagram of a surface acoustic wave transducer according to different exemplary embodiments of the present invention.
[0014] The annotations in the attached figures are explained as follows:
[0015] 11: First busbar;
[0016] 12: First electrode refers to;
[0017] 13: First figurative reference;
[0018] 21: Second busbar;
[0019] 22: Second electrode refers to;
[0020] 23: The second figurative reference;
[0021] 31: Reflector;
[0022] 41-45: Zones 1 to 5. Detailed Implementation
[0023] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof. These are only some embodiments of the invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.
[0024] like Figure 1 As shown, the distance between the ends of adjacent first electrode finger 12 and second electrode finger 22 in the direction perpendicular to the direction of surface acoustic wave propagation (e.g., Figure 1 (As shown by the dashed line) defines the aperture or finger strip aperture. For example... Figure 1 In the surface acoustic wave transducer shown, the aperture size and lateral position (i.e., the position in the direction perpendicular to the direction of surface acoustic wave propagation or along the extension direction of the electrode fingers) are constant, which leads to the problem of lateral energy leakage of the acoustic wave.
[0025] The present invention divides the interdigitated electrode structure into multiple regions along the propagation direction of surface acoustic waves. In at least one region, the aperture size of the interdigitated electrodes is equal (this region is called the aperture equal region). Furthermore, a discontinuous weighting is formed between the aperture equal region and its adjacent regions, thereby effectively suppressing transverse energy leakage of acoustic waves or suppressing transverse modes.
[0026] The technical solution of the present invention will now be described by way of example with reference to the accompanying drawings.
[0027] Figure 2 This is a top view schematic diagram of a surface acoustic wave transducer according to an exemplary embodiment of the present invention. Figure 2As shown, the surface acoustic wave transducer includes a piezoelectric layer (not shown) and interdigitated electrodes. The interdigitated electrodes are disposed on the surface of the piezoelectric layer. Each interdigitated electrode includes a first busbar 11, a plurality of first electrode fingers 12 connected to the first busbar 11, a second busbar 21, and a plurality of second electrode fingers 22 connected to the second busbar 21. The plurality of first electrode fingers 12 and the plurality of second electrode fingers 22 are staggered in the direction of surface acoustic wave propagation and have overlapping regions. The interdigitated electrodes also include first dummy fingers 13 and second dummy fingers 23. The plurality of first dummy fingers 13 and the plurality of first electrode fingers 12 are alternately connected to the first busbar 11. The plurality of second dummy fingers 23 and the plurality of second electrode fingers 22 are alternately connected to the second busbar 21. Each first electrode finger 12 and a corresponding second dummy finger 23 are positioned opposite each other and spaced apart. Each second electrode finger 22 and a corresponding first dummy finger 13 are positioned opposite each other and spaced apart. As known to those skilled in the art, reflectors 31 are also disposed on both sides of the interdigitated electrodes.
[0028] like Figure 2 As shown, the interdigitated electrodes include multiple regions arranged in the direction of surface acoustic wave propagation. These multiple regions include at least adjacent first region 41 and second region 42. The line connecting the ends of the multiple second electrode fingers 22 within the first region 41 defines a first trace (see...). Figure 2 (The upper dashed line of the first region 41). The line connecting the ends of the multiple second electrode fingers 22 within the second region 42 defines the second trace (see...). Figure 2 (Upper dashed line of the second region 42). The adjacent ends of the first and second traces in the direction of surface acoustic wave propagation are staggered in the direction of extension of the electrode fingers to form discontinuous weighting. The apertures of the finger strips in the first region 41 are all equal.
[0029] In this invention, the adjacent ends of the first trace and the second trace in the direction of propagation of the surface acoustic wave are offset in the direction of extension of the electrode finger, indicating that there is a step in the portion of the first trace and the second trace near the adjacent ends in the direction of propagation of the surface acoustic wave in the direction of extension of the electrode finger. This step makes the first trace and the second trace discontinuous, so as to form a discontinuous weighting.
[0030] For example, in Figure 2 And what was mentioned later Figures 5-7 In the illustrated embodiment, both the first and second traces are straight lines, parallel but not collinear. That is, the first trace, based on its extension trend, will not connect with the second trace due to this non-collinearity, thus creating a discontinuity between the two traces and forming a discontinuous weighted sum. In the following, the first trace extending as a straight line is referred to as the first straight line, and the second trace extending as a straight line is referred to as the second straight line.
[0031] For example, as mentioned later... Figures 8-9In the illustrated embodiment, the first trace in the first region 41 and the second trace in the second region 42 are offset in the extension direction of the electrode finger. Even if the first trace in the first region 41 extends into the second region according to its extension trend, it does not connect with the second trace in the second region 42. This results in a step between the two adjacent ends of the first trace in the first region and the second trace in the second region in the extension direction of the electrode finger. This step makes the first trace and the second trace discontinuous, forming a discontinuous weighting. It can be considered that the adjacent ends in the propagation direction of the surface acoustic wave are offset by a distance in the extension direction of the electrode finger, and the distance is not less than twice the width of the electrode finger.
[0032] In optional embodiments, such as Figure 2 As shown, the finger strip apertures in the second region 42 are all equal.
[0033] In an optional embodiment, although not shown, Figure 2 At least two finger strips within the second region 42 may have unequal apertures. This can also be mentioned later. Figures 5-9 Variations of the illustrated embodiment.
[0034] In optional embodiments, such as Figure 2 And what was mentioned later Figures 5-7 As shown, both the first and second traces are straight lines, but the invention is not limited thereto. Figure 8 As shown, both the first and second traces can be curves. Although not shown, in other embodiments, the first trace can be a straight line and the second trace can be a curve, or vice versa. Furthermore, the trace can also be a broken line (see, for example, [link to relevant documentation]). Figure 9 (or other forms). Different forms of traces can appear simultaneously in the same area. For example, traces in the same area include combinations of straight lines, curves, and broken lines. Different forms of traces can also appear in different areas. For example, traces in the first area 41 can be straight lines, traces in the second area 42 can be curves, and traces in the third area 43 can be broken lines. All of these are within the protection scope of this invention.
[0035] In optional embodiments, such as Figure 2 as well as Figures 5-7 As shown, both the first and second straight lines extend along the direction of surface acoustic wave propagation.
[0036] In an optional embodiment, although not shown, the first and second straight lines may be at a non-zero angle to the direction of propagation of the surface acoustic wave.
[0037] In optional embodiments, such as Figure 2 as well as Figures 5-7As shown, the line connecting the ends of the plurality of first electrode fingers 12 within the first region 41 defines a third trace (see, for example, [reference needed]). Figure 2 (The lower dashed line of the first region 41). The line connecting the ends of the plurality of first electrode fingers 12 within the second region 42 defines the fourth trace (see, for example, see...). Figure 2 (Lower dashed line of the second region 42). Optional, such as... Figure 2 as well as Figures 5-7 As shown, the third trace can be a straight line (hereinafter referred to as the third straight line), and the fourth trace can be a straight line (hereinafter referred to as the fourth straight line).
[0038] It is easy to understand that since the finger strip apertures are all equal in the first region 41, the third line is parallel to the first line. Similarly, when the finger strip apertures are all equal in the second region 42, the fourth line is parallel to the second line.
[0039] In optional embodiments, such as Figure 2 And what was mentioned later Figures 5-7 As shown, the third and / or fourth straight lines extend along the propagation direction of surface acoustic waves.
[0040] In optional embodiments, such as Figure 2 And what was mentioned later Figure 5 and Figure 7 As shown, the third and fourth lines are parallel but not collinear.
[0041] In optional embodiments, such as Figure 2 And what was mentioned later Figure 5 and Figure 7 As shown, the finger strip aperture in the first region 41 is different from the finger strip aperture in the second region 42.
[0042] In optional embodiments, such as Figure 2 As shown, the difference between the aperture of the finger strip in the first region 41 and the aperture of the finger strip in the second region 42 is 0.5 to 10 times the wavelength of the surface acoustic wave transducer, for example, 0.5, 2, 5, 8, 10 times, etc. This aperture difference within the above range can improve the shear wave suppression effect while preventing the filter performance from deteriorating.
[0043] In optional embodiments, such as Figure 2 As shown, the interdigitated electrode also includes a third region 43, a fourth region 44, and a fifth region 45. The finger strip apertures within each region are equal. The finger strip apertures between adjacent regions are unequal.
[0044] In optional embodiments, such as Figure 2 As shown, the aperture of at least three adjacent regions in the direction of surface acoustic wave propagation first increases and then decreases.
[0045] In an optional embodiment, although not shown, the aperture corresponding to at least three adjacent regions in the direction of surface acoustic wave propagation can be decreased and then increased.
[0046] In optional embodiments, such as Figure 2 As shown, the number of first electrode fingers 12 in the first region 41 is different from the number of first electrode fingers 12 in the second region 42.
[0047] In an optional embodiment, although not shown, the number of first electrode fingers 12 in the first region 41 and the number of first electrode fingers 12 in the second region 42 may be equal.
[0048] In optional embodiments, the number of first electrode fingers in the first region 41 or the number of first electrode fingers in the second region 42 is greater than or equal to 2 and less than or equal to 200. For example, the number can be 2, 8, 10, 20, 30, 50, 80, 100, 150, 200, etc. For example, such as... Figure 2 As shown, the number of first electrode fingers 12 in the first region 41 is 6, and the number of first electrode fingers 12 in the second region 42 is 3.
[0049] In optional embodiments, such as Figure 2 As shown, the number of first electrode fingers 12 in at least three adjacent regions along the direction of surface acoustic wave propagation alternates between increasing and decreasing.
[0050] In an optional embodiment, although not shown, the number of first electrode fingers 12 in at least three adjacent regions in the direction of propagation of the surface acoustic wave increases or decreases sequentially.
[0051] In an optional embodiment, although not shown, the number of first electrode fingers 12 in at least three adjacent regions in the direction of propagation of the surface acoustic wave can be increased and then decreased or decreased and then increased.
[0052] Figure 3 The test results are illustrated in the figure below. Figure 2 The admittance of a surface acoustic wave transducer varies with frequency. Figure 3 In the diagram, the horizontal axis represents frequency, and the vertical axis represents the magnitude or real part of the admittance. Curve 1 represents the change of the admittance magnitude with frequency, and curve 2 represents the change of the real part of the admittance with frequency. Curve 1 shows that the frequencies corresponding to the resonant peak and anti-resonant peak of the admittance are 1.6 GHz and 1.67 GHz, respectively. Curve 2 shows that the change of the real part of the admittance with frequency is relatively smooth between the resonant peak and the anti-resonant peak, indicating that the structure of this invention has a good suppression effect on transverse modes.
[0053] Figure 4 The chart shows a comparison of the test results, which respectively demonstrate... Figure 1 and Figure 2 Curve showing the real part of the admittance of a surface acoustic wave transducer as a function of frequency. Figure 4 In the middle, curve 3 corresponds to Figure 1 The curve of the real part of the admittance of a surface acoustic wave transducer as a function of frequency, curve 4 corresponds to... Figure 2 The curve showing the real part of the admittance of a surface acoustic wave transducer as a function of frequency. Figure 4 It can be seen from this that Figure 2 The curve of the real part of the admittance of a surface acoustic wave transducer as a function of frequency is compared to... Figure 1 The curve of the real part of the admittance of the surface acoustic wave transducer as a function of frequency is smoother, indicating that the surface acoustic wave transducer in this invention has a better suppression effect on transverse modes.
[0054] Figure 5 This is a top view schematic diagram of a surface acoustic wave transducer according to another exemplary embodiment of the present invention. It is related to... Figure 2 The difference between surface acoustic wave transducers and medium acoustic wave transducers is that... Figure 5 In the process, the first region 41 and the second region 42 form a group in the direction of surface acoustic wave propagation. The multiple regions of the interdigital electrode include multiple groups of first regions 41 and second regions 42 arranged periodically in the direction of surface acoustic wave propagation. In the direction of surface acoustic wave propagation, the aperture of the finger strip corresponding to each region increases or decreases alternately in the direction of surface acoustic wave propagation and exhibits periodic changes.
[0055] Figure 6 This is a top view schematic diagram of a surface acoustic wave transducer according to yet another exemplary embodiment of the present invention. It is related to... Figure 5 The difference between the two surface acoustic wave (SAW) transducers lies in the fact that the finger strip apertures in the first region 41 and the second region 42 are of equal size, but their positions in the extension direction of the electrode fingers (hereinafter referred to as the lateral positions) are different. In a more specific embodiment, the lateral positions of the finger strip apertures exhibit periodic changes in the propagation direction of the SAW wave. The lateral positions of the finger strip apertures are defined by the positions of the ends of the two adjacent electrode fingers corresponding to the apertures in the extension direction of the electrode fingers.
[0056] Figure 7 This is a top view schematic diagram of a surface acoustic wave transducer according to another exemplary embodiment of the present invention. It is related to... Figure 5 or Figure 6 The difference between surface acoustic wave transducers and traditional transducers is that the difference is only on one side of the interdigitated electrodes. Figure 7 On the upper side of the middle, the adjacent ends of two traces in adjacent regions are staggered, on the other side of the interdigitated electrode ( Figure 7 (On the lower side of the middle), the adjacent ends of the two traces in the adjacent area are not staggered or collinear.
[0057] Figure 8This is a top view schematic diagram of a surface acoustic wave transducer according to another exemplary embodiment of the present invention. Its difference from the surface acoustic wave transducer in example 2 is that... Figure 8 The first trace in the equation is not a straight line, but a curve. Optionally, this curve can be a trigonometric function curve. For example... Figure 8 As shown, the traces in each region are all curves. Figure 8 The curve shown is an example; the trace can also be other curve forms, such as arcs.
[0058] exist Figure 8 In the first region 41, the finger strip apertures are equal, but the finger strip apertures in the first region 41 are different from those in the second region.
[0059] Figure 9 This is a top view schematic diagram of a surface acoustic wave transducer according to another exemplary embodiment of the present invention. It is related to... Figure 2 The difference between surface acoustic wave transducers and medium acoustic wave transducers is that... Figure 9 The first trace in the image is not a straight line, but a broken line. For example... Figure 9 As shown, the traces in each region are all broken lines. Figure 9 The polyline in the image is just one example; the form of a polyline can also vary, for example, a polyline can have multiple inflection points.
[0060] exist Figure 9 In the first region 41, the finger strip apertures are equal, but the finger strip apertures in the first region 41 are different from those in the second region.
[0061] In an optional embodiment, the number of regions in the direction of surface acoustic wave propagation is greater than or equal to 3.
[0062] In optional embodiments, the number of regions along the propagation direction of the surface acoustic wave can be adjusted according to different frequency ranges; a larger number of regions results in better suppression of transverse modes. Generally, the lower the frequency, the more severe the transverse mode suppression. Therefore, for low-frequency applications (e.g., <1.2 GHz), the number of regions can be appropriately increased, while for mid-to-high-frequency applications (e.g., >1.2 GHz), the number of regions can be appropriately decreased. Optionally, the applicable frequency of the surface acoustic wave transducer is less than 1.2 GHz, and the total number of regions distributed along the propagation direction of the surface acoustic wave, including the interdigitated electrodes, is greater than or equal to 5.
[0063] In the above embodiments of the present invention, dummy electrodes are provided, such that: the first busbar 11 is provided with a first dummy finger 13 that is spaced apart from the second electrode finger 22 to form a first gap, and the second busbar 21 is provided with a second dummy finger 23 that is spaced apart from the first electrode finger 12 to form a second gap. Thus, for example, the line connecting the first gaps in the first region 41 is parallel to a first straight line, and the line connecting the first gaps in the second region 42 is parallel to a second straight line. However, the present invention is not limited to this, and dummy fingers may not be provided.
[0064] In this invention, the leftmost region is designated as the first region in the accompanying drawings; however, this is merely exemplary. In this invention, the first region can be any other region along the propagation direction of the surface acoustic wave.
[0065] In the accompanying drawings of this invention, the first trace of each region has only one trace shape, but the invention is not limited to this. It is also possible that the first trace includes multiple types of curves, broken lines and straight lines that are connected to each other.
[0066] Based on the above, in this invention, the phrase "adjacent ends in the direction of surface acoustic wave propagation are offset in the direction of extension of the electrode finger" can be further defined as follows: at least one of the first and second traces has a non-linear portion near its adjacent end, and the adjacent ends in the direction of surface acoustic wave propagation are offset by a distance in the direction of extension of the electrode finger, the distance being not less than twice the width of the electrode finger; or the portions of the first and second traces near their adjacent ends are non-collinear linear portions.
[0067] Furthermore, the number of regions shown in the accompanying drawings of this invention is merely exemplary.
[0068] In the accompanying drawings of this invention, the entire area of the interdigital electrode is weighted. However, this invention is not limited to this. As long as a portion of the area is weighted and satisfies the condition that "the adjacent ends of the first trace and the second trace in the direction of propagation of the surface acoustic wave are staggered in the direction of extension of the electrode fingers; and the apertures of the finger strips in the first area are equal", it is also within the protection scope of this invention.
[0069] In the foregoing embodiments of the present invention, the finger strip apertures within each region are the same. However, as mentioned above, one or more regions among the multiple regions may also be regions with different finger strip apertures. Regions with the same finger strip apertures may be one or more, and these are all within the protection scope of the present invention.
[0070] The present invention also provides an apparatus comprising the aforementioned surface acoustic wave transducer. This apparatus may be a filter or other device or apparatus that utilizes the aforementioned surface acoustic wave transducer.
[0071] In optional embodiments, the filter described above can be a filter with a POI (piezoelectric-on-insulator) substrate or a TC-SAW (Temperature Compensated Surface Acoustic Wave) filter. Filters of these types typically exhibit more severe transverse modes; the solution of this invention can effectively suppress these transverse modes.
[0072] Based on the above, the present invention proposes the following technical solution:
[0073] 1. A surface acoustic wave transducer, comprising:
[0074] piezoelectric layer;
[0075] Interdigitated electrodes, disposed on the surface of the piezoelectric layer, include: a first busbar and a plurality of first electrode fingers connected to the first busbar, a second busbar and a plurality of second electrode fingers connected to the second busbar;
[0076] The interdigitated electrodes include multiple regions arranged in the direction of surface acoustic wave propagation. These multiple regions include at least adjacent first and second regions. A line connecting the tips of multiple second electrode fingers within the first region defines a first trace, and a line connecting the tips of multiple second electrode fingers within the second region defines a second trace.
[0077] in:
[0078] The adjacent ends of the first and second traces in the direction of surface acoustic wave propagation are offset in the direction of extension of the electrode fingers.
[0079] The finger strips in the first region have the same aperture.
[0080] 2. The surface acoustic wave transducer according to claim 1, wherein:
[0081] The finger strips in the second region have the same aperture.
[0082] 3. The surface acoustic wave transducer according to claim 2, wherein:
[0083] Both the first trace and the second trace are straight lines.
[0084] 4. The surface acoustic wave transducer according to 3, wherein:
[0085] The first trace and the second trace are parallel but not collinear.
[0086] 5. The surface acoustic wave transducer according to 3, wherein:
[0087] The first trace and / or the second trace extend along the propagation direction of the surface acoustic wave.
[0088] 6. The surface acoustic wave transducer according to 3, wherein:
[0089] The line connecting the ends of a plurality of first electrode fingers in the first region defines a third trace, and the line connecting the ends of a plurality of first electrode fingers in the second region defines a fourth trace, both the third trace and the fourth trace being straight lines.
[0090] 7. The surface acoustic wave transducer according to claim 2, wherein:
[0091] The first trace and / or the second trace are curves or broken lines.
[0092] 8. The surface acoustic wave transducer according to claim 2, wherein:
[0093] The first region and the second region form a group in the direction of surface acoustic wave propagation, and the plurality of regions include at least two groups of first regions and second regions arranged periodically in the direction of surface acoustic wave propagation.
[0094] 9. The surface acoustic wave transducer according to any one of 2-8, wherein:
[0095] The aperture of the finger strip in the first region is different from that in the second region.
[0096] 10. The surface acoustic wave transducer according to claim 9, wherein:
[0097] The difference between the aperture of the finger strip in the first region and the aperture of the finger strip in the second region is 0.5 to 10 times the wavelength of the surface acoustic wave transducer.
[0098] 11. The surface acoustic wave transducer according to claim 9, wherein:
[0099] The plurality of regions includes at least three adjacent regions, and in the direction of surface acoustic wave propagation, the aperture of the finger strip corresponding to the at least three regions increases or decreases sequentially.
[0100] 12. The surface acoustic wave transducer according to 9, wherein:
[0101] The plurality of regions includes at least three adjacent regions, and in the direction of surface acoustic wave propagation, the aperture of the finger strip corresponding to the at least three regions first increases and then decreases or first decreases and then increases.
[0102] 13. The surface acoustic wave transducer according to any one of 2-8, wherein:
[0103] The diameter of the finger strip in the first region is the same as the diameter of the finger strip in the second region.
[0104] 14. The surface acoustic wave transducer according to claim 2, wherein:
[0105] The number of first electrode fingers in the first region is equal to the number of first electrode fingers in the second region.
[0106] 15. The surface acoustic wave transducer according to claim 2, wherein:
[0107] The number of first electrode fingers in the first region is different from the number of first electrode fingers in the second region.
[0108] 16. The surface acoustic wave transducer according to 15, wherein:
[0109] The number of first electrode fingers increases or decreases in at least three adjacent regions along the direction of surface acoustic wave propagation.
[0110] 17. The surface acoustic wave transducer according to 15, wherein:
[0111] The number of first electrode fingers in at least three adjacent regions along the direction of surface acoustic wave propagation either increases and then decreases or decreases and then increases.
[0112] 18. The surface acoustic wave transducer according to claim 2, wherein:
[0113] The number of first electrode fingers in the first region or the number of first electrode fingers in the second region is greater than or equal to 2 and less than or equal to 200.
[0114] 19. The surface acoustic wave transducer according to claim 1, wherein:
[0115] At least two finger strips in the second region have unequal apertures.
[0116] 20. The surface acoustic wave transducer according to 1 or 19, wherein:
[0117] The first trace is a curve, a broken line, or a straight line; or
[0118] The first trace includes multiple types of curves, broken lines, and straight lines that are connected to each other.
[0119] 21. The surface acoustic wave transducer according to claim 1, wherein:
[0120] The first busbar is provided with a first virtual finger that is spaced apart from the second electrode finger to form a first gap, and the second busbar is provided with a second virtual finger that is spaced apart from the first electrode finger to form a second gap;
[0121] The line connecting the first gaps in the first region is parallel to the first trace, and the line connecting the first gaps in the second region is parallel to the second trace.
[0122] 22. The surface acoustic wave transducer according to claim 1, wherein:
[0123] The total number of regions is greater than or equal to 3.
[0124] 23. The surface acoustic wave transducer according to 22, wherein:
[0125] The applicable frequency of the surface acoustic wave transducer is less than 1.2 GHz, and the total number of regions of the plurality of regions is greater than or equal to 5.
[0126] 24. The surface acoustic wave transducer according to claim 1, wherein:
[0127] At least one of the first and second traces has a non-linear portion near its adjacent ends, and the adjacent ends are offset in the direction of propagation of the surface acoustic wave by a distance not less than twice the width of the electrode finger in the direction of extension of the electrode finger; or
[0128] Even if the first trace extends into the second region according to its extension trend, it will not connect with the second trace in the second region; or
[0129] The portions of the first and second traces near their adjacent ends are non-collinear straight lines.
[0130] 25. An apparatus comprising a surface acoustic wave transducer as described in any one of 1-24.
[0131] 26. The apparatus according to 25, wherein:
[0132] The device includes a filter with a POI substrate or a TC-SAW filter.
[0133] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A surface acoustic wave transducer, comprising: piezoelectric layer; Interdigitated electrodes, disposed on the surface of the piezoelectric layer, include: a first busbar and a plurality of first electrode fingers connected to the first busbar, a second busbar and a plurality of second electrode fingers connected to the second busbar; The interdigitated electrodes include multiple regions arranged in the direction of surface acoustic wave propagation. These multiple regions include at least adjacent first and second regions. A line connecting the tips of multiple second electrode fingers within the first region defines a first trace, and a line connecting the tips of multiple second electrode fingers within the second region defines a second trace. in: The adjacent ends of the first and second traces in the direction of propagation of surface acoustic waves are offset in the direction of extension of the electrode fingers, and the first and second traces are not collinear. There are multiple equal finger strip apertures in the first region, and the distance between the ends of any adjacent first electrode finger and second electrode finger in the direction perpendicular to the direction of surface acoustic wave propagation defines the finger strip aperture in the first region. The transducer has an axis that divides each region into an upper and a lower portion, with the first trace and the second trace located on the same side of the axis.
2. The surface acoustic wave transducer according to claim 1, wherein: The finger strips in the second region have the same aperture.
3. The surface acoustic wave transducer according to claim 2, wherein: Both the first trace and the second trace are straight lines.
4. The surface acoustic wave transducer according to claim 3, wherein: The first trace and the second trace are parallel.
5. The surface acoustic wave transducer according to claim 3, wherein: The first trace and / or the second trace extend along the propagation direction of the surface acoustic wave.
6. The surface acoustic wave transducer according to claim 3, wherein: The line connecting the ends of a plurality of first electrode fingers in the first region defines a third trace, and the line connecting the ends of a plurality of first electrode fingers in the second region defines a fourth trace, both the third trace and the fourth trace being straight lines.
7. The surface acoustic wave transducer according to claim 2, wherein: The first trace and / or the second trace are curves or broken lines.
8. The surface acoustic wave transducer according to claim 2, wherein: The first region and the second region form a group in the direction of surface acoustic wave propagation, and the plurality of regions include at least two groups of first regions and second regions arranged periodically in the direction of surface acoustic wave propagation.
9. The surface acoustic wave transducer according to any one of claims 2-8, wherein: The aperture of the finger strip in the first region is different from that in the second region.
10. The surface acoustic wave transducer according to claim 9, wherein: The difference between the aperture of the finger strip in the first region and the aperture of the finger strip in the second region is 0.5 to 10 times the wavelength of the surface acoustic wave transducer.
11. The surface acoustic wave transducer according to claim 9, wherein: The plurality of regions includes at least three adjacent regions, and in the direction of surface acoustic wave propagation, the aperture of the finger strip corresponding to the at least three regions increases or decreases sequentially.
12. The surface acoustic wave transducer according to claim 9, wherein: The plurality of regions includes at least three adjacent regions, and in the direction of surface acoustic wave propagation, the aperture of the finger strip corresponding to the at least three regions first increases and then decreases or first decreases and then increases.
13. The surface acoustic wave transducer according to any one of claims 2-8, wherein: The diameter of the finger strip in the first region is the same as the diameter of the finger strip in the second region.
14. The surface acoustic wave transducer according to claim 2, wherein: The number of first electrode fingers in the first region is equal to the number of first electrode fingers in the second region.
15. The surface acoustic wave transducer according to claim 2, wherein: The number of first electrode fingers in the first region is different from the number of first electrode fingers in the second region.
16. The surface acoustic wave transducer according to claim 15, wherein: The number of first electrode fingers increases or decreases in at least three adjacent regions along the direction of surface acoustic wave propagation.
17. The surface acoustic wave transducer according to claim 15, wherein: The number of first electrode fingers in at least three adjacent regions along the direction of surface acoustic wave propagation either increases and then decreases or decreases and then increases.
18. The surface acoustic wave transducer according to claim 2, wherein: The number of first electrode fingers in the first region or the number of first electrode fingers in the second region is greater than or equal to 2 and less than or equal to 200.
19. The surface acoustic wave transducer according to claim 1, wherein: At least two finger strips in the second region have unequal apertures.
20. The surface acoustic wave transducer according to claim 1 or 19, wherein: The first trace is a curve, a broken line, or a straight line; or The first trace includes multiple types of curves, broken lines, and straight lines that are connected to each other.
21. The surface acoustic wave transducer according to claim 1, wherein: The first busbar is provided with a first virtual finger that is spaced apart from the second electrode finger to form a first gap, and the second busbar is provided with a second virtual finger that is spaced apart from the first electrode finger to form a second gap; The line connecting the first gaps in the first region is parallel to the first trace, and the line connecting the first gaps in the second region is parallel to the second trace.
22. The surface acoustic wave transducer according to claim 1, wherein: The total number of regions is greater than or equal to 3.
23. The surface acoustic wave transducer according to claim 22, wherein: The applicable frequency of the surface acoustic wave transducer is less than 1.2 GHz, and the total number of regions of the plurality of regions is greater than or equal to 5.
24. The surface acoustic wave transducer according to claim 1, wherein: At least one of the first and second traces has a non-straight portion near its adjacent ends, and the adjacent ends are offset by a distance in the direction of extension of the electrode finger in the direction of propagation of the surface acoustic wave, the distance being not less than twice the width of the electrode finger. or Even if the first trace extends into the second region according to its extension trend, it will not connect with the second trace in the second region; or The portions of the first and second traces near their adjacent ends are non-collinear straight lines.
25. An apparatus comprising a surface acoustic wave transducer as described in any one of claims 1-24.
26. The apparatus according to claim 25, wherein: The device includes a filter with a POI substrate or a TC-SAW filter.