Surface acoustic wave transducer and apparatus comprising same

Abstract

The present invention relates to a surface acoustic wave transducer and an apparatus comprising same. The surface acoustic wave transducer comprises: a piezoelectric layer; and an interdigital electrode which is provided on the surface of the piezoelectric layer and comprises a first bus bar, a plurality of first electrode fingers connected to the first bus bar, a second bus bar, and a plurality of second electrode fingers connected to the second bus bar. The interdigital electrode comprises a plurality of regions arranged in the propagation direction of a surface acoustic wave, the plurality of regions at least comprising a first region and a second region which are adjacent to each other. Connecting lines of ends of the plurality of second electrode fingers in the first region define a first trace, and connecting lines of ends of the plurality of second electrode fingers in the second region define a second trace, adjacent ends of the first trace and the second trace being offset in the extension direction of the electrode fingers, and the apertures of fingered stripes in the first region being equal.

Description

Surface acoustic wave transducer and device including the same Technical Field

[0001] Embodiments of the present invention relate to the field of semiconductors, and in particular to a surface acoustic wave transducer and a device comprising the same. Background Art

[0002] With the continuous improvement of mobile communication technology, the number of communication frequency bands has increased dramatically. The guard intervals between frequency bands of different communication systems are getting 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 is a schematic diagram of the structure of the current resonator. As shown in Figure 1, the resonator includes interdigitated electrodes and reflectors 31 located on both sides of the interdigitated electrodes. The interdigitated electrodes include a first bus bar 11 and a second bus bar 21. A plurality of first electrode fingers 12 and a plurality of first dummy fingers 13 are alternately arranged on the first bus bar 11. A plurality of second electrode fingers 22 and a plurality of second dummy fingers 23 are alternately arranged on the second bus bar 21. In the direction of surface acoustic wave propagation (i.e., the horizontal direction in the figure), the plurality of first electrode fingers 12 and the plurality of second electrode fingers 22 are arranged in an alternating pattern. The first electrode fingers 12 and the second dummy fingers 23 are arranged opposite each other with gaps therebetween. The second electrode fingers 22 and the first dummy fingers 13 are arranged opposite each other with gaps therebetween. A line connecting the ends of all first electrode fingers 12 (or a line connecting the gaps between the ends of all first electrode fingers 12) and a line connecting the ends of all second electrode fingers 22 (or a line connecting the gaps between the ends of all second electrode fingers 22) are straight lines along the direction of surface acoustic wave propagation. The resonator shown in FIG1 has the problem of lateral acoustic wave energy leakage, which seriously deteriorates the steepness of the resonator's transition band and the flatness within the passband, and causes spurious resonances in the resonator.

[0004] Currently, when suppressing transverse modes, most methods add a layer of metal to the ends of the resonator's fingers to reduce the speed of sound in this area. While this method can effectively suppress transverse modes, it is sensitive to the size and weight of the mass load, requiring high processing requirements and increasing process costs. Another technique for suppressing transverse modes is to design the interdigital electrodes into an inclined structure, which results in an increase in the area of ​​the interdigital electrodes, which is detrimental to reducing the cost and size of the filter.

[0005] Summary of the Invention

[0006] The present invention is proposed to alleviate or solve at least one aspect of the above-mentioned problems in the prior art.

[0007] According to one aspect of an embodiment of the present invention, a surface acoustic wave transducer is proposed, comprising: a piezoelectric layer; an interdigitated electrode, arranged on the surface of the piezoelectric layer, comprising: a first bus bar and a plurality of first electrode fingers connected to the first bus bar, a second bus bar and a plurality of second electrode fingers connected to the second bus bar; the interdigitated electrode comprises a plurality of regions arranged in the propagation direction of the surface acoustic wave, the plurality of regions comprising at least adjacent first 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 apertures in the first region are equal.

[0008] According to one aspect of an embodiment of the present invention, a device is provided, comprising the above-mentioned surface acoustic wave transducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The following description and accompanying drawings may better help understand these and other features and advantages of various embodiments disclosed herein, wherein like reference numerals denote like components throughout the drawings, wherein:

[0010] FIG1 is a schematic top view of a known resonator;

[0011] FIG2 is a schematic top view of a surface acoustic wave transducer according to an exemplary embodiment of the present invention;

[0012] FIG3 is a test result diagram, exemplarily showing a curve of the admittance of the surface acoustic wave transducer in FIG2 varying with frequency;

[0013] FIG4 is a comparison diagram of the test results, which respectively shows the curves of the real part of the admittance of the surface acoustic wave transducers in FIG1 and FIG2 as a function of frequency;

[0014] 5 to 9 are schematic top views of surface acoustic wave transducers according to different exemplary embodiments of the present invention.

[0015] The reference numerals are explained as follows: 11: first bus bar; 12: first electrode finger; 13: first virtual finger; 21: second bus bar; 22: second electrode finger; 23: second virtual finger; 31: reflector; 41-45: first to fifth regions. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further specifically described below through examples and in conjunction with the accompanying drawings. In the specification, the same or similar drawing numbers indicate the same or similar parts. 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 understood as a limitation of the present invention. Some embodiments of the invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field fall within the scope of protection of the present invention.

[0017] As shown in Figure 1, the distance between the ends of adjacent first and second electrode fingers 12 and 22 in a direction perpendicular to the surface acoustic wave propagation direction (indicated by the dashed line in Figure 1) defines the aperture or finger-strip aperture. In a surface acoustic wave transducer such as that shown in Figure 1, the aperture size and lateral position (i.e., the position perpendicular to the surface acoustic wave propagation direction or along the extension direction of the electrode fingers) are constant, which can lead to the problem of lateral acoustic wave energy leakage.

[0018] The present invention divides the interdigitated electrode structure into multiple regions along the propagation direction of the surface acoustic wave. The apertures of the fingers in at least one region are equal in size (this region is called the equal aperture region), and discontinuous weighting is formed between the equal aperture region and the adjacent regions, thereby effectively suppressing the lateral energy leakage of the acoustic wave or suppressing the lateral mode.

[0019] The technical solution of the present invention is exemplarily described below with reference to the accompanying drawings.

[0020] Figure 2 is a schematic top view of a surface acoustic wave transducer according to an exemplary embodiment of the present invention. As shown in Figure 2, the surface acoustic wave transducer includes a piezoelectric layer (not shown) and interdigitated electrodes. The interdigitated electrodes are arranged on the surface of the piezoelectric layer. The interdigitated electrodes include a first bus bar 11, a plurality of first electrode fingers 12 connected to the first bus bar 11, a second bus bar 21, and a plurality of second electrode fingers 22 connected to the second bus bar 21. The plurality of first electrode fingers 12 and the plurality of second electrode fingers 22 are arranged alternately in the propagation direction of the surface acoustic wave and have overlapping areas. 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 bus bar 11. The plurality of second dummy fingers 23 and the plurality of second electrode fingers 22 are alternately connected to the second bus bar 21. Each first electrode finger 12 and a corresponding second dummy finger 23 are arranged opposite each other and spaced apart. Each second electrode finger 22 and a corresponding first dummy finger 13 are arranged opposite each other and spaced apart. As known to those skilled in the art, reflectors 31 are further provided on both sides of the interdigital electrodes.

[0021] As shown in FIG2 , the interdigitated electrode includes multiple regions arranged in the propagation direction of the surface acoustic wave. The multiple regions include at least a first region 41 and a second region 42 that are adjacent to each other. The line connecting the ends of the multiple second electrode fingers 22 in the first region 41 defines a first trace (see the upper dashed line of the first region 41 in FIG2 ). The line connecting the ends of the multiple second electrode fingers 22 in the second region 42 defines a second trace (see the upper dashed line of the second region 42 in FIG2 ). The adjacent ends of the first trace and the second trace in the propagation direction of the surface acoustic wave are staggered in the extension direction of the electrode fingers to form discontinuous weighting. The finger apertures in the first region 41 are all equal.

[0022] In the present invention, the adjacent ends of the first trace and the second trace in the propagation direction of the surface acoustic wave are staggered in the extension direction of the electrode fingers, which means that there is a step in the extension direction of the electrode fingers in the parts of the first trace and the second trace close to the adjacent ends along the propagation direction of the surface acoustic wave. The step makes the first trace discontinuous with the second trace to form discontinuous weighting.

[0023] For example, in the embodiments shown in FIG2 and the subsequent FIG5-7, the first and second traces are both straight lines that are parallel but not collinear. This means that the first trace does not connect with the second trace due to the step created by the non-collinearity in the first trace's extension trend, resulting in a discontinuous weighting between the first and second traces. Hereinafter, the straight extension of the first trace is referred to as the first straight line, and the straight extension of the second trace is referred to as the second straight line.

[0024] For another example, in the embodiments shown in Figures 8 and 9 discussed later, the first trace in the first region 41 and the second trace in the second region 42 are offset in the direction in which the electrode fingers extend. Even if the first trace in the first region 41 extends into the second region in the same direction as the first trace, it does not connect with the second trace in the second region 42. Consequently, a step exists between the adjacent ends of the first trace in the first region and the second trace in the second region in the direction in which the electrode fingers extend. This step discontinuities the first trace and the second trace, thereby forming discontinuous weighting. It can be considered that the adjacent ends in the direction of surface acoustic wave propagation are offset in the direction in which the electrode fingers extend by a distance that is no less than twice the electrode finger width.

[0025] In an optional embodiment, as shown in FIG2 , the apertures of the fingers in the second region 42 are all equal.

[0026] In an optional embodiment, although not shown, the apertures of at least two fingers in the second region 42 in Figure 2 may be unequal, which can also be used as a variation of the embodiments shown in Figures 5 to 9 mentioned later.

[0027] In an optional embodiment, as shown in FIG2 and the subsequently mentioned FIG5-7, the first trace and the second trace are both straight lines, but the present invention is not limited to this. As shown in FIG8, the first trace and the second trace may also be curves. Although not shown, in another embodiment, the first trace may be a straight line and the second trace may be a curve, or vice versa. In addition, the trace may also be a broken line (for example, see FIG9) or other forms. Traces of different forms may appear in the same area at the same time, for example, the traces in the same area include a combination of straight lines, curves, and broken lines; traces of different forms may also appear in different areas, for example, the trace in the first area 41 may be a straight line, the trace in the second area 42 may be a curve, and the trace in the third area 43 may be a broken line. These are all within the scope of protection of the present invention.

[0028] In an optional embodiment, as shown in FIG. 2 and FIG. 5 - FIG. 7 , both the first straight line and the second straight line extend along the propagation direction of the surface acoustic wave.

[0029] In an alternative embodiment, although not shown, the first straight line and the second straight line may form a non-zero angle with the propagation direction of the surface acoustic wave.

[0030] In an alternative embodiment, as shown in FIG2 and FIG5-7 , a line connecting the ends of the plurality of first electrode fingers 12 in the first region 41 defines a third trace (see, for example, the dashed line below the first region 41 in FIG2 ). A line connecting the ends of the plurality of first electrode fingers 12 in the second region 42 defines a fourth trace (see, for example, the dashed line below the second region 42 in FIG2 ). Alternatively, as shown in FIG2 and FIG5-7 , 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).

[0031] It is easy to understand that since the apertures of the fingers in the first region 41 are all equal, the third straight line is parallel to the first straight line. Similarly, when the apertures of the fingers in the second region 42 are all equal, the fourth straight line is parallel to the second straight line.

[0032] In an optional embodiment, as shown in FIG. 2 and the subsequently mentioned FIG. 5 to FIG. 7 , the third straight line and / or the fourth straight line extends along the propagation direction of the surface acoustic wave.

[0033] In an optional embodiment, as shown in FIG. 2 and the subsequently mentioned FIG. 5 and FIG. 7 , the third straight line and the fourth straight line are parallel but not collinear.

[0034] In an optional embodiment, as shown in FIG. 2 and the subsequently mentioned FIG. 5 and FIG. 7 , the finger aperture in the first region 41 is different from the finger aperture in the second region 42 .

[0035] In an optional embodiment, as shown in FIG2 , the difference between the finger apertures in the first region 41 and the finger apertures 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, etc. The aperture difference within the above numerical range can improve the shear wave suppression effect while preventing the filter performance from deteriorating.

[0036] In an optional embodiment, as shown in FIG2 , the interdigitated electrode further includes a third region 43, a fourth region 44, and a fifth region 45. The apertures of the fingers in each region are equal, while the apertures of the fingers between adjacent regions are not equal.

[0037] In an optional embodiment, as shown in FIG2 , the apertures corresponding to at least three adjacent regions in the propagation direction of the surface acoustic wave first increase and then decrease.

[0038] In an optional embodiment, although not shown, the apertures corresponding to at least three adjacent regions in the propagation direction of the surface acoustic wave may first decrease and then increase.

[0039] In an optional embodiment, as shown in FIG. 2 , 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 .

[0040] In an alternative 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.

[0041] In an optional embodiment, 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, and can be, for example, 2, 8, 10, 20, 30, 50, 80, 100, 150, 200, etc. For example, as shown in FIG2 , 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.

[0042] In an optional embodiment, as shown in FIG2 , the number of first electrode fingers 12 in at least three adjacent regions in the propagation direction of the surface acoustic wave increases and decreases alternately.

[0043] In an optional embodiment, although not shown, the numbers of the first electrode fingers 12 in at least three adjacent regions in the propagation direction of the surface acoustic wave increase or decrease sequentially.

[0044] In an optional embodiment, although not shown, the number of first electrode fingers 12 in at least three adjacent regions in the propagation direction of the surface acoustic wave may first increase and then decrease, or first decrease and then increase.

[0045] FIG3 is a test result diagram, which exemplarily shows the curve of the change of the admittance of the surface acoustic wave transducer in FIG2 with frequency. In FIG3, the horizontal axis represents the frequency, and the vertical axis represents the modulus or real part of the admittance. Among them, curve 1 represents the curve of the change of the modulus of the admittance with frequency, and curve 2 represents the curve of the change of the real part of the admittance with frequency. According to curve 1, it can be seen that the frequencies corresponding to the resonance peak and antiresonance peak of the admittance are 1.6 GHz and 1.67 GHz respectively. According to curve 2, it can be seen that between the resonance peak and the antiresonance peak, the change of the real part of the admittance with frequency is relatively smooth, indicating that the structure of the present invention has a good inhibitory effect on the transverse mode.

[0046] FIG4 is a comparison chart of the test results, showing the curves of the real part of the admittance of the SAW transducers in FIG1 and FIG2 as a function of frequency. In FIG4, Curve 3 corresponds to the curve of the real part of the admittance of the SAW transducer in FIG1 as a function of frequency, and Curve 4 corresponds to the curve of the real part of the admittance of the SAW transducer in FIG2 as a function of frequency. As can be seen from FIG4, the curve of the real part of the admittance of the SAW transducer in FIG2 as a function of frequency is smoother than the curve of the real part of the admittance of the SAW transducer in FIG1 as a function of frequency, indicating that the SAW transducer of the present invention has a better suppression effect on transverse modes.

[0047] Figure 5 is a schematic top view of a surface acoustic wave transducer according to another exemplary embodiment of the present invention. It differs from the surface acoustic wave transducer in Figure 2 in that, in Figure 5, first regions 41 and second regions 42 form a group in the direction of surface acoustic wave propagation, and the multiple regions of the interdigitated electrode include multiple groups of first regions 41 and second regions 42 periodically arranged in the direction of surface acoustic wave propagation. In the direction of surface acoustic wave propagation, the finger apertures corresponding to each region alternately increase and decrease in a periodic manner.

[0048] FIG6 is a schematic top view of a surface acoustic wave transducer according to another exemplary embodiment of the present invention. It differs from the surface acoustic wave transducer in FIG5 in that the finger apertures in the first region 41 and the finger apertures in the second region 42 are equal in size, but their positions in the electrode finger extension direction (hereinafter referred to as lateral positions) are different. In a more specific embodiment, the lateral positions of the finger apertures vary periodically in the propagation direction of the surface acoustic wave. The lateral positions of the finger apertures are defined by the positions of the ends of two adjacent electrode fingers corresponding to the apertures in the electrode finger extension direction.

[0049] FIG7 is a schematic top view of a surface acoustic wave transducer according to another exemplary embodiment of the present invention. This transducer differs from the surface acoustic wave transducers of FIG5 or FIG6 in that the adjacent ends of two traces in adjacent regions are staggered only on one side of the interdigital electrodes (the upper side in FIG7 ). On the other side of the interdigital electrodes (the lower side in FIG7 ), the adjacent ends of two traces in adjacent regions are not staggered or collinear.

[0050] FIG8 is a schematic top view of a surface acoustic wave transducer according to another exemplary embodiment of the present invention. The difference between FIG8 and the surface acoustic wave transducer in FIG2 is that the first trace in FIG8 is not a straight line but a curve. Alternatively, the curve may be a trigonometric curve. As shown in FIG8 , the traces in each region are all curved. The curves in FIG8 are exemplary only; the traces may also take other curved forms, such as arcs.

[0051] In FIG. 8 , the finger apertures in the first region 41 are equal, but the finger apertures in the first region 41 are different from those in the second region.

[0052] Figure 9 is a schematic top view of a surface acoustic wave transducer according to another exemplary embodiment of the present invention. Unlike the surface acoustic wave transducer in Figure 2 , the first trace in Figure 9 is not a straight line but a broken line. As shown in Figure 9 , the traces in each region are broken lines. The broken lines in Figure 9 are merely examples; their form can vary, for example, they can have multiple inflection points.

[0053] In FIG. 9 , the finger apertures in the first region 41 are equal, but the finger apertures in the first region 41 are different from those in the second region.

[0054] In an optional embodiment, the number of regions in the propagation direction of the surface acoustic wave is greater than or equal to three.

[0055] In an optional embodiment, the number of regions along the propagation direction of the surface acoustic wave can be adjusted according to different frequency ranges, and a greater number of regions improves the transverse mode suppression effect. Generally, the lower the frequency, the more severe the transverse mode. Therefore, for low frequencies (e.g., frequencies <1.2 GHz), the number of regions can be appropriately increased, and for medium and high frequencies (e.g., frequencies >1.2 GHz), the number of regions can be appropriately reduced. 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 included in the interdigitated electrode is greater than or equal to 5.

[0056] In the above-described embodiments of the present invention, dummy electrodes are provided. Thus, first bus bar 11 is provided with first dummy fingers 13 spaced apart from second electrode fingers 22 to form first gaps, and second bus bar 21 is provided with second dummy fingers 23 spaced apart from first electrode fingers 12 to form second gaps. Thus, for example, a line connecting the first gaps in first region 41 is parallel to a first straight line, and a line connecting the first gaps in second region 42 is parallel to a second straight line. However, the present invention is not limited to this, and dummy fingers may be omitted.

[0057] In the present invention, the leftmost region in the drawings is the first region, but this is merely exemplary. In the present invention, the first region may be any other region in the propagation direction of the surface acoustic wave.

[0058] In the drawings of the present invention, the first trace of each region has only one trace form, but the present invention is not limited thereto. The first trace may also include multiple types of curves, broken lines and straight lines connected to each other.

[0059] Based on the above, in the present invention, "adjacent ends in the propagation direction of the surface acoustic wave are offset in the extension direction of the electrode fingers" can be further defined as: the portion of at least one of the first trace and the second trace close to the adjacent end is a non-linear portion, and the adjacent ends in the propagation direction of the surface acoustic wave are offset in the extension direction of the electrode fingers by a distance that is not less than 2 times the width of the electrode fingers; or the portion of the first trace and the second trace close to the adjacent end is a non-collinear straight portion.

[0060] In addition, in the drawings in this application, the number of regions is only exemplary.

[0061] In the drawings of the present invention, the entire area of ​​the interdigitated electrode is provided with weighting, but the present invention is not limited thereto. As long as a partial area is provided with weighting and satisfies the requirements of "the adjacent ends of the first trace and the second trace in the propagation direction of the surface acoustic wave are staggered in the extension direction of the electrode fingers; the finger apertures in the first area are equal", it is also within the protection scope of the present invention.

[0062] In the aforementioned embodiments of the present invention, for each area, the finger aperture within is the same, but as mentioned earlier, one or more areas among the multiple areas may also be areas with different finger apertures, and the areas with the same finger aperture may be one or more, which are all within the scope of protection of the present invention.

[0063] The present invention further provides a device comprising the aforementioned surface acoustic wave transducer, which may be a filter or other device or apparatus using the aforementioned surface acoustic wave transducer.

[0064] In an optional embodiment, the filter may be a filter having a POI (piezoelectric-on-insulator) substrate or a TC-SAW (temperature-compensated surface acoustic wave) filter. These filters typically have more severe transverse modes, and the solution of the present invention can effectively suppress these transverse modes.

[0065] Based on the above, the present invention proposes the following technical solutions:

[0066] 1. A surface acoustic wave transducer, comprising:

[0067] Piezoelectric layer;

[0068] an interdigitated electrode disposed on a surface of the piezoelectric layer, comprising: a first bus bar and a plurality of first electrode fingers connected to the first bus bar, a second bus bar and a plurality of second electrode fingers connected to the second bus bar;

[0069] The interdigitated electrode includes a plurality of regions arranged in a propagation direction of a surface acoustic wave, the plurality of regions including at least a first region and a second region adjacent to each other, a line connecting ends of a plurality of second electrode fingers in the first region defining a first trace, and a line connecting ends of a plurality of second electrode fingers in the second region defining a second trace,

[0070] in:

[0071] Ends of the first trace and the second trace adjacent to each other in the propagation direction of the surface acoustic wave are offset in the extending direction of the electrode fingers;

[0072] The apertures of the fingers in the first area are equal.

[0073] 2. The surface acoustic wave transducer according to item 1, wherein:

[0074] The apertures of the fingers in the second area are equal.

[0075] 3. The surface acoustic wave transducer according to 2, wherein:

[0076] The first trace and the second trace are both straight lines.

[0077] 4. The surface acoustic wave transducer according to 3, wherein:

[0078] The first trace and the second trace are parallel but not co-linear.

[0079] 5. The surface acoustic wave transducer according to item 3, wherein:

[0080] The first trace and / or the second trace extends along a propagation direction of the surface acoustic wave.

[0081] 6. The surface acoustic wave transducer according to item 3, wherein:

[0082] A line connecting the ends of the plurality of first electrode fingers in the first region defines a third trace, and a line connecting the ends of the plurality of first electrode fingers in the second region defines a fourth trace. Both the third trace and the fourth trace are straight lines.

[0083] 7. The surface acoustic wave transducer according to item 2, wherein:

[0084] The first trace and / or the second trace is a curve or a broken line.

[0085] 8. The surface acoustic wave transducer according to item 2, wherein:

[0086] The first region and the second region form a group in the propagation direction of the surface acoustic wave, and the plurality of regions include at least two groups of first regions and second regions periodically arranged in the propagation direction of the surface acoustic wave.

[0087] 9. The surface acoustic wave transducer according to any one of 2 to 8, wherein:

[0088] The finger apertures in the first region are different from the finger apertures in the second region.

[0089] 10. The surface acoustic wave transducer according to 9, wherein:

[0090] The difference between the finger aperture in the first region and the finger aperture in the second region is 0.5 to 10 times the wavelength of the surface acoustic wave transducer.

[0091] 11. The surface acoustic wave transducer according to item 9, wherein:

[0092] The multiple regions include at least three adjacent regions, and in the propagation direction of the surface acoustic wave, the finger apertures corresponding to the at least three regions increase or decrease in sequence.

[0093] 12. The surface acoustic wave transducer according to item 9, wherein:

[0094] The multiple regions include at least three adjacent regions. In the propagation direction of the surface acoustic wave, the finger apertures corresponding to the at least three regions first increase and then decrease, or first decrease and then increase.

[0095] 13. The surface acoustic wave transducer according to any one of 2 to 8, wherein:

[0096] The finger aperture diameter in the first area is equal to the finger aperture diameter in the second area.

[0097] 14. The surface acoustic wave transducer according to item 2, wherein:

[0098] The number of the first electrode fingers in the first region is equal to the number of the first electrode fingers in the second region.

[0099] 15. The surface acoustic wave transducer according to item 2, wherein:

[0100] The number of the first electrode fingers in the first region is different from the number of the first electrode fingers in the second region.

[0101] 16. The surface acoustic wave transducer according to 15, wherein:

[0102] The number of first electrode fingers in at least three adjacent regions in the propagation direction of the surface acoustic wave increases or decreases.

[0103] 17. The surface acoustic wave transducer according to 15, wherein:

[0104] In the propagation direction of the surface acoustic wave, the number of the first electrode fingers in at least three adjacent regions first increases and then decreases, or first decreases and then increases.

[0105] 18. The surface acoustic wave transducer according to item 2, wherein:

[0106] 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.

[0107] 19. The surface acoustic wave transducer according to item 1, wherein:

[0108] The apertures of at least two fingers in the second area are unequal.

[0109] 20. The surface acoustic wave transducer according to 1 or 19, wherein:

[0110] The first trace is a curve, a broken line, or a straight line; or

[0111] The first trace includes multiple types of curves, broken lines and straight lines connected to each other.

[0112] 21. The surface acoustic wave transducer according to item 1, wherein:

[0113] The first bus bar is provided with a first dummy finger spaced opposite to the second electrode finger to form a first gap, and the second bus bar is provided with a second dummy finger spaced opposite to the first electrode finger to form a second gap;

[0114] A line connecting the first gaps in the first region is parallel to the first trace, and a line connecting the first gaps in the second region is parallel to the second trace.

[0115] 22. The surface acoustic wave transducer according to claim 1, wherein:

[0116] The total number of the plurality of regions is greater than or equal to 3.

[0117] 23. The surface acoustic wave transducer according to 22, wherein:

[0118] The applicable frequency of the surface acoustic wave transducer is less than 1.2 GHz, and the total number of the multiple regions is greater than or equal to 5.

[0119] 24. The surface acoustic wave transducer according to item 1, wherein:

[0120] A portion of at least one of the first trace and the second trace close to adjacent ends is a non-linear portion, and adjacent ends in the propagation direction of the surface acoustic wave are staggered 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; or

[0121] Even if the first trace extends into the second area according to the extension trend of the first trace, it does not connect with the second trace in the second area; or

[0122] Portions of the first trace and the second trace near adjacent ends are non-collinear straight line portions.

[0123] 25. A device comprising the surface acoustic wave transducer according to any one of 1 to 24.

[0124] 26. The device according to 25, wherein:

[0125] The device includes a filter having a POI substrate or a TC-SAW filter.

[0126] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A surface acoustic wave transducer, comprising: Piezoelectric layer; An interdigitated electrode, disposed on a surface of the piezoelectric layer, comprising: a first bus bar and a plurality of first electrode fingers connected to the first bus bar, a second bus bar and a plurality of second electrode fingers connected to the second bus bar; The interdigitated electrode includes a plurality of regions arranged in a propagation direction of the surface acoustic wave, the plurality of regions at least including a first region and a second region adjacent to each other, a line connecting ends of a plurality of second electrode fingers in the first region defines a first trace, and a line connecting ends of a plurality of second electrode fingers in the second region defines a second trace, in: Ends of the first trace and the second trace that are adjacent in the propagation direction of the surface acoustic wave are offset in the extension direction of the electrode fingers; The apertures of the fingers in the first area are equal.

2. The surface acoustic wave transducer according to claim 1, wherein: The apertures of the fingers in the second area are equal.

3. The surface acoustic wave transducer according to claim 2, wherein: The first trace and the second trace are both straight lines.

4. The surface acoustic wave transducer according to claim 3, wherein: The first trace and the second trace are parallel but not co-linear.

5. The surface acoustic wave transducer according to claim 3, wherein: The first trace and / or the second trace extends along a propagation direction of the surface acoustic wave.

6. The surface acoustic wave transducer according to claim 3, wherein: A line connecting the ends of the plurality of first electrode fingers in the first region defines a third trace line, and a line connecting the ends of the plurality of first electrode fingers in the second region defines a fourth trace line, and the third trace line and the fourth trace line are both straight lines.

7. The surface acoustic wave transducer according to claim 2, wherein: The first trace and / or the second trace is a curve or a broken line.

8. The surface acoustic wave transducer according to claim 2, wherein: The first region and the second region form a group in the propagation direction of the surface acoustic wave, and the plurality of regions include at least two groups of first regions and second regions periodically arranged in the propagation direction of the surface acoustic wave.

9. The surface acoustic wave transducer according to any one of claims 2 to 8, wherein: The finger aperture in the first region is different from the finger aperture in the second region.

10. The surface acoustic wave transducer according to claim 9, wherein: The difference between the finger aperture in the first region and the finger aperture 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 multiple regions include at least three adjacent regions, and in the propagation direction of the surface acoustic wave, the finger apertures corresponding to the at least three regions increase or decrease in sequence.

12. The surface acoustic wave transducer according to claim 9, wherein: The multiple regions include at least three adjacent regions, and in the propagation direction of the surface acoustic wave, finger apertures corresponding to the at least three regions increase first and then decrease, or decrease first and then increase.

13. The surface acoustic wave transducer according to any one of claims 2 to 8, wherein: The finger aperture diameter in the first area is equal to the finger aperture diameter in the second area.

14. The surface acoustic wave transducer according to claim 2, wherein: The number of the first electrode fingers in the first region is equal to the number of the first electrode fingers in the second region.

15. The surface acoustic wave transducer according to claim 2, wherein: The number of the first electrode fingers in the first region is different from the number of the first electrode fingers in the second region.

16. The surface acoustic wave transducer according to claim 15, wherein: The number of first electrode fingers in at least three adjacent regions in the propagation direction of the surface acoustic wave increases or decreases.

17. The surface acoustic wave transducer according to claim 15, wherein: In the propagation direction of the surface acoustic wave, the number of the first electrode fingers in at least three adjacent regions increases first and then decreases, or decreases first and then increases.

18. The surface acoustic wave transducer according to claim 2, wherein: The number of the first electrode fingers in the first region or the number of the 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 fingers 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 line includes multiple types of curves, broken lines and straight lines connected to each other.

21. The surface acoustic wave transducer according to claim 1, wherein: The first bus bar is provided with a first dummy finger spaced opposite to the second electrode finger to form a first gap, and the second bus bar is provided with a second dummy finger spaced opposite to the first electrode finger to form a second gap; A line connecting the first gaps in the first region is parallel to the first trace, and a 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: A total number of regions of the plurality 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 the multiple regions is greater than or equal to 5.

24. The surface acoustic wave transducer according to claim 1, wherein: A portion of at least one of the first trace and the second trace close to adjacent ends is a non-linear portion, and adjacent ends in the propagation direction of the surface acoustic wave are staggered by a distance in the extension direction of the electrode finger, and the distance is not less than 2 times the width of the electrode finger; or Even if the first trace extends into the second region according to the extension trend of the first trace, it does not connect with the second trace in the second region; or Portions of the first trace and the second trace near the adjacent ends are non-collinear straight line portions.

25. A device comprising the surface acoustic wave transducer according to any one of claims 1 to 24.

26. The apparatus of claim 25, wherein: The device includes a filter having a POI substrate or a TC-SAW filter.

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