Surface acoustic wave resonator and filter

Abstract

The present invention discloses a surface acoustic wave resonator and filter. The resonator comprises an interdigital structure comprising a first interdigital region and a second interdigital region; the first interdigital region comprises a plurality of first fingers, and the second interdigital region comprises a plurality of second fingers; a reflective grating disposed on either side of the interdigital structure in a first direction, the reflective grating being coplanar with the plurality of first fingers and the plurality of second fingers; the reflective grating and the plurality of first fingers intersecting perpendicularly with each other, and the reflective grating and the plurality of second fingers intersecting perpendicularly with each other; in the first direction, each first finger is arranged opposite each second finger, with a gap formed between the first and second fingers; in the second direction, the plurality of first fingers are arranged in parallel, and the plurality of second fingers are arranged in parallel; the first direction is perpendicular to the second direction. The present invention can reduce lateral energy leakage in the first direction and suppress high-order spurious modes of the surface acoustic wave resonator in the first and second directions.

Description

Technical Field

[0001] The present invention relates to the technical field of resonators, and in particular to a surface acoustic wave resonator and a filter. Background Art

[0002] Surface acoustic wave (SAW) devices boast high quality factors and miniaturization, making them widely used in wireless communications, sensing, and filtering. However, in practical applications, SAW device performance can be severely impacted by high-order modal interference, including transverse and longitudinal modes. This interference not only reduces the resonator's frequency purity but also leads to energy leakage and increased signal noise, compromising the device's overall performance.

[0003] The generation of transverse modes is primarily due to the lateral leakage of acoustic energy through the IDT. This transversely propagating energy deviates from the main propagation direction and forms parasitic signals, interfering with the device's normal operation. Higher-order longitudinal modes, caused by the structural characteristics of the interdigital electrodes, generate additional resonant peaks in the main propagation direction, leading to signal artifacts and reducing the device's frequency selectivity and stability. Summary of the Invention

[0004] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is how to improve the ability to suppress high-order modes.

[0005] In order to solve at least one of the above-mentioned technical problems, the present invention discloses a surface acoustic wave resonator and a filter.

[0006] According to one aspect of the present disclosure, there is provided a surface acoustic wave resonator, comprising:

[0007] An interdigital structure comprising a first interdigital region and a second interdigital region; the first interdigital region comprises a plurality of first fingers, and the second interdigital region comprises a plurality of second fingers;

[0008] a reflective grating disposed on both sides of the interdigitated structure in a first direction, the reflective grating being located in the same plane as the plurality of first fingers and the plurality of second fingers; the reflective grating intersecting the plurality of first fingers, and the reflective grating intersecting the plurality of second fingers;

[0009] In the first direction, each first finger is arranged opposite to each second finger, and an opposing distance is formed between the first finger and the second finger;

[0010] In the second direction, the plurality of first fingers are arranged in parallel, and the plurality of second fingers are arranged in parallel.

[0011] In some possible embodiments, in the first interdigitated region, in the second direction, each of the first fingers has a first finger width, and any two adjacent first fingers among the plurality of first fingers have a first finger spacing;

[0012] The sum of the first finger width and the first finger spacing is a first stripe period; the first stripe period ranges from 0.3 μm to 3.5 μm;

[0013] A ratio of the first finger width to the first stripe period is a first duty cycle corresponding to the first finger; and the first duty cycle ranges from 0.4 to 0.65.

[0014] In some possible embodiments, each of the first fingers has a first finger length extending along the first direction;

[0015] The length of the first fingers is determined according to the order of the first fingers in the second direction and the number of the plurality of first fingers.

[0016] In some possible embodiments, in the second interdigitated region, in the second direction, each second finger has a second finger width, and any two adjacent second fingers in the plurality of second fingers have a second finger spacing;

[0017] The sum of the second finger width and the second finger spacing is the second stripe period; the second stripe period ranges from 0.3 μm to 3.5 μm;

[0018] A ratio of the second finger width to the second stripe period is a second duty cycle corresponding to the second finger; and the second duty cycle ranges from 0.4 to 0.65.

[0019] In some possible embodiments, each of the second fingers has a second finger length extending along the first direction;

[0020] The length of the second fingers is determined according to the order of the second fingers in the second direction and the number of the plurality of second fingers.

[0021] In some possible embodiments, the interdigitated structure includes a plurality of first fingers and a plurality of opposing spacings formed between the plurality of second fingers;

[0022] The plurality of opposing intervals are parallel to each other in the second direction and are staggeredly distributed around a central axis of the interdigital structure.

[0023] In some possible embodiments, the opposing spacing has a range of 0.2 μm to 10.5 μm.

[0024] In some possible embodiments, the reflective grating includes a plurality of reflective grating strips arranged in parallel in the first direction;

[0025] In the first direction, each reflective grating has a grating width; the grating width is determined according to the first stripe period and / or the second stripe period.

[0026] In some possible embodiments, any two adjacent reflective gratings form a grating spacing in the first direction; the grating spacing is determined according to the first stripe period and / or the second stripe period.

[0027] In some possible embodiments, a size of each of the reflective gratings in the second direction is greater than or equal to a size of the interdigital structure in the second direction.

[0028] In some possible embodiments, the plurality of reflective gratings, the first finger strips, and the second finger strips form a plurality of reflective holes;

[0029] The plurality of reflective holes are arranged at first intervals in the first direction and at second intervals in the second direction.

[0030] In some possible embodiments, the multiple reflective holes have the same shape and size, and the reflective holes are rectangular or diamond-shaped;

[0031] When the shape of the plurality of reflective holes is rhombus, the included angle between any of the reflective gratings and the first finger strips and / or the second finger strips in the first direction ranges from 60° to 85°.

[0032] According to a second aspect of the present disclosure, a filter is provided, comprising any one of the surface acoustic wave resonators described above.

[0033] The implementation of the present invention has the following beneficial effects:

[0034] In the present invention, the surface acoustic wave resonator includes a finger region and a reflection grating. In the finger region, the parallel and spaced fingers can uniformly excite the surface acoustic wave, avoiding uneven acoustic wave excitation caused by the irregular distribution of the fingers, thereby generating a clear and stable main propagation mode and improving the consistency of the frequency response. The reflection grating is arranged on both sides of the finger region and is located in the same plane as the finger region and intersects with each other, so that the reflection grating can efficiently reflect the laterally propagating acoustic wave energy and guide it back to the main propagation direction, thereby improving the utilization efficiency of the acoustic wave energy and reducing the interference of the lateral mode on the resonator performance. In addition, setting the reflection grating and the finger region in the same plane can reduce the complexity of the multi-layer manufacturing process, thereby reducing alignment errors and manufacturing costs; at the same time, it can avoid the problem of interlayer scattering and improve energy utilization efficiency and signal purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 A first structural diagram of a surface acoustic wave resonator provided in an embodiment of the present invention;

[0037] Figure 2 A second structural diagram of a surface acoustic wave resonator provided in an embodiment of the present invention;

[0038] Figure 3 A third structural diagram of a surface acoustic wave resonator provided by an embodiment of the present invention;

[0039] Figure 4 A first structural diagram corresponding to the reflective grating provided in an embodiment of the present invention;

[0040] Figure 5 A second structural schematic diagram corresponding to the reflective grating provided in an embodiment of the present invention;

[0041] Figure 6 A third structural diagram corresponding to the reflective grating provided in an embodiment of the present invention;

[0042] Figure 7 A fourth structural diagram corresponding to the reflective grating provided in an embodiment of the present invention;

[0043] Figure 8 Admittance diagrams corresponding to comparisons of two resonators provided in a specific embodiment of the present invention;

[0044] Figure 9 A dB value curve diagram comparing two resonators provided in a specific embodiment of the present invention.

[0045] The reference numerals may include: 100 - interdigital structure, 110 - first interdigital region, 111 - first finger strip, 120 - second interdigital region, 121 - second finger strip; 130 - opposing distance;

[0046] 200-reflection grid, 210-reflection grid bar, 220-reflection hole;

[0047] 300-center axis;

[0048] W1- first finger width, W2- second finger width, W3- grid width;

[0049] S1 is the first finger spacing, S2 is the second finger spacing, and S3 is the grid spacing. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this invention.

[0051] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way are interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or server that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0052] Various exemplary embodiments, features, and aspects of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0053] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0054] The term "and / or" herein simply describes an association relationship between associated objects, indicating that three relationships can exist. For example, "A and / or B" can represent the existence of three situations: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" herein refers to any combination of at least two of any one or more of a plurality of items. For example, "at least one of A, B, and C" can represent any one or more elements selected from the set consisting of A, B, and C.

[0055] In addition, numerous specific details are provided in the following detailed description to better illustrate the present disclosure. Those skilled in the art will appreciate that the present disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art are not described in detail in order to highlight the main points of the present disclosure.

[0056] Figure 1 FIG. 1 shows a first structural diagram of a surface acoustic wave resonator provided by an embodiment of the present invention; FIG. Figure 1 As shown, the first direction is the horizontal x direction, and the second direction is the vertical y direction; a surface acoustic wave resonator may include:

[0057] The interdigital structure 100 includes a first interdigital region 110 and a second interdigital region 120; the first interdigital region 110 includes a plurality of first fingers 111, and the second interdigital region 120 includes a plurality of second fingers 121; the interdigital structure 100 further includes a plurality of opposing spacings 130 formed between the plurality of first fingers 111 and the plurality of second fingers 121; the plurality of opposing spacings 130 are parallel to each other in the second direction and are staggered around the central axis 300 of the interdigital structure 100;

[0058] The reflective grating 200 is disposed on both sides of the interdigital structure 100 in the first direction. The reflective grating 200, the plurality of first fingers 111, and the plurality of second fingers 121 are located in the same plane. The reflective grating 200 and the plurality of first fingers 111 intersect with each other, and the reflective grating 200 and the plurality of second fingers 121 intersect with each other.

[0059] In the first direction, each first finger 111 is arranged opposite to each second finger 121 , and an opposing distance 130 is formed between the first finger 111 and the second finger 121 ;

[0060] In the second direction, the plurality of first fingers 111 are arranged in parallel, and the plurality of second fingers 121 are arranged in parallel.

[0061] In a specific embodiment, Figure 1 As shown, a surface acoustic wave resonator may include an interdigital structure 100 and a reflective grating 200 disposed on either side of the interdigital structure 100, wherein the interdigital structure 100 and the reflective grating 200 are perpendicular and located in the same layer. The interdigital structure 100 can be considered an interdigital transducer, comprising a plurality of fingers and opposing spacings 130 formed by the fingers opposing each other in a first direction. The plurality of opposing spacings 130 are parallel to each other in a second direction and staggered around the central axis 300 of the interdigital structure 100; the plurality of fingers are arranged to form an interdigital structure for stimulating acoustic wave signals.

[0062] Specifically, the interdigitated structure 100 can be fabricated on a piezoelectric material substrate, such as quartz, lithium tantalate, or lithium niobate. The substrate can include a single layer or multiple layers of materials, each of which can support passivation, temperature compensation, power handling, mode suppression, and the like. Key materials include lithium niobate (LN), lithium tantalate (LT), aluminum nitride (AlN), silicon dioxide (SiO2), polycrystalline silicon (ploy-Si), amorphous silicon, silicon nitride (SiN), silicon oxynitride (SiON), scandium-doped aluminum nitride (AlScN), non-conductive materials (such as silicon (Si), doped silicon, sapphire, silicon carbide (SiC), fused silica, glass, diamond, etc.), and combinations or doped compounds of the aforementioned materials. The properties of piezoelectric materials enable electrical signals to be converted into acoustic waves. The interdigital structure 100 can be divided into a first interdigital region 110 including first fingers 111 and a second interdigital region 120 including second fingers 121 according to an opposing spacing 130. The opposing spacing 130 is the distance between the first fingers 111 and the second fingers 121 in the first direction. The interdigital structure 100 is divided into the first interdigital region 110 and the second interdigital region 120 according to the opposing spacing 130. Specifically, the fingers on the left side of the opposing spacing 130 are the first fingers 111, and the area on the left side of the opposing spacing 130 including the first fingers 111 is the first interdigital region 110. The fingers on the right side of the opposing spacing 130 are the second fingers 121, and the area on the right side of the opposing spacing 130 including the second fingers 121 is the second interdigital region 120. It should be noted that the division of the first interdigital region 110 and the second interdigital region 120 in the present invention is for the purpose of facilitating the description of the surface acoustic wave resonator structure, and does not necessarily require the interdigital structure 100 to be divided into the first interdigital region 110 and the second interdigital region 120 in actual applications. In addition, the rectangular frame in any of the figures in the specification is only used to clearly identify the location of the structure, and does not describe its actual structure, size, etc.

[0063] In an embodiment of the present invention, the interdigital structure 100 excites acoustic waves and, in conjunction with the opposing spacing 130, suppresses high-order mode clutter. The reflective gratings 200 on both sides of the interdigital structure 100 reflect the energy of the transverse mode, thereby reducing the lateral leakage of signal energy and further improving signal quality.

[0064] Figure 2 A second structural diagram of a surface acoustic wave resonator provided in an embodiment of the present invention is used to identify the structure, parameters, etc. related to the first interdigital region 110 in the surface acoustic wave resonator; Figure 2 As shown, in the first interdigitated area 110 , in the second direction, each of the first fingers 111 has a first finger width W1 , and among the plurality of first fingers 111 , any two adjacent first fingers 111 have a first finger spacing S1 ;

[0065] The sum of the first finger width W1 and the first finger spacing S1 is a first stripe period; the first stripe period ranges from 0.3 μm to 3.5 μm;

[0066] A ratio of the first finger width W1 to the first stripe period is a first duty cycle corresponding to the first finger 111 ; the first duty cycle ranges from 0.4 to 0.65.

[0067] Each of the first fingers 111 has a first finger length extending along the first direction;

[0068] The length of the first fingers is determined according to the order of the first fingers 111 in the second direction and the number of the plurality of first fingers 111 .

[0069] In a specific embodiment, the first interdigitated area 110 includes a plurality of first fingers 111 arranged in parallel in the second direction, wherein each first finger 111 has a first finger width W1 in the second direction, and each first finger 111 also has a first finger length extending along the first direction in the first direction.

[0070] Regarding the first finger width W1, in the second direction, a first finger spacing S1 is formed between any two adjacent first fingers 111. Multiple first fingers 111 form multiple first finger spacings S1. The sum of the first finger spacing S1 and the first finger width W1 is the first stripe period. The first stripe period ranges from 0.3 μm to 3.5 μm, and preferably ranges from 0.85 μm to 2.5 μm. For example, the first stripe period can be 1.5 μm. The ratio of the first finger width W1 to the first stripe period is the first duty cycle. The first duty cycle ranges from 0.4 to 0.65, and preferably can be 0.5. The first stripe period is a basic parameter of the periodic structure, which can be used to describe the periodicity of the first fingers 111 and the arrangement of the first finger spacing S1. It is the basic unit of repetition of the first fingers 111 and the first finger spacing S1. The first duty cycle describes the proportion of the effective portion (i.e., the first finger width W1) to the first stripe period.

[0071] The first finger length L1 is determined by the order of the first fingers 111 in the second direction and the number of the first fingers 111. In addition, the first finger length L1 may also be related to a proportional coefficient. Specifically, the first finger length L1 may be calculated using the following formula:

[0072]

[0073] Wherein, i is the order of the first fingers 111 in the first interdigitated structure 100 in the second direction, n is the number of the plurality of first fingers 111 in the first interdigitated structure 100, A is the first proportional coefficient, and B is the second proportional coefficient; wherein, n ≥ 20 and preferably 75, A ≤ 30 μm and preferably 5 μm, B ≥ 20*first strip period and preferably B = 40*first strip period.

[0074] By limiting the range of values ​​for the first stripe period and the first duty cycle, the first finger width W1, first finger length, and first finger spacing S1 are adjusted. These limited dimensional settings can improve the suppression of high-order spurious modes in both the longitudinal and transverse directions. They also ensure that the first finger length and first finger width W1 are appropriate, thereby avoiding etching difficulties caused by excessively small length and / or width, or photolithography distortion caused by excessive length and / or width.

[0075] Figure 3 The third structural diagram of the surface acoustic wave resonator provided in the embodiment of the present invention is used to identify the structure, parameters, etc. related to the second interdigital region 120 in the surface acoustic wave resonator; Figure 3 In the second interdigitated region 120 , in the second direction, each second finger 121 has a second finger width W2 , and any two adjacent second fingers 121 in the plurality of second fingers 121 have a second finger spacing S2 ;

[0076] The sum of the second finger width W2 and the second finger spacing S2 is a second stripe period; the second stripe period ranges from 0.3 μm to 3.5 μm;

[0077] The ratio of the second finger width W2 to the second stripe period is a second duty cycle corresponding to the second finger 121 ; the second duty cycle ranges from 0.4 to 0.65.

[0078] Each of the second fingers 121 has a second finger length extending along the first direction;

[0079] The length of the second fingers is determined according to the order of the second fingers 121 in the second direction and the number of the plurality of second fingers 121 .

[0080] In a specific embodiment, the multiple second fingers 121 included in the second interdigitated area 120 are arranged in parallel in the second direction, wherein each second finger 121 has a second finger width W2 in the second direction, and each second finger 121 also has a second finger length extending along the first direction in the first direction.

[0081] Regarding the second finger width W2, in the second direction, a second finger spacing S2 is formed between any two adjacent second fingers 121. Multiple second fingers 121 each form a plurality of second finger spacings S2. The sum of the second finger spacing S2 and the second finger width W2 is the second stripe period. The second stripe period ranges from 0.3 μm to 3.5 μm, preferably from 0.85 μm to 2.5 μm. For example, the second stripe period can be 1.5 μm. The ratio of the second finger width W2 to the second stripe period is the second duty cycle. The second duty cycle ranges from 0.4 to 0.65, preferably 0.5. The second stripe period is a fundamental parameter of a periodic structure, describing the periodicity of the second fingers 121 and the arrangement of the second finger spacing S2. It is the basic unit of repetition of the second fingers 121 and the second finger spacing S2. The second duty cycle describes the proportion of the active portion (i.e., the second finger width W2) to the second stripe period.

[0082] The second finger length L2 is determined by the order of the second fingers 121 in the second direction and the number of the second fingers 121. In addition, the second finger length L2 may also be related to a proportional coefficient. Specifically, the second finger length L2 may be calculated using the following formula:

[0083]

[0084] Wherein, j is the order of the second fingers 121 in the second interdigitated structure 100 in the second direction, m is the number of the plurality of second fingers 121 in the second interdigitated structure 100, A is the second proportional coefficient, and B is the second proportional coefficient; wherein, m ≥ 20 and preferably 75, A ≤ 30 μm and preferably 5 μm, B ≥ 20*second strip period and preferably B = 40*second strip period.

[0085] Furthermore, to ensure that the first fingers 111 and the second fingers 121 are aligned with each other, the first finger width W1 and the second finger width W2 must be equal, and the first finger spacing S1 and the second finger spacing S2 must be equal. By adjusting the lengths of the first fingers 111 and the second fingers 121, the opposing spacing 130 between the first fingers 111 and the second fingers 121 is changed, thereby adjusting the distribution or characteristics of the interdigital structure 100, changing the excitation coefficients of the first fingers 111 and / or the second fingers 121, and reducing the excitation efficiency of high-order modes, thereby suppressing longitudinal and transverse high-order clutter modes.

[0086] like Figure 1-Figure 3 As shown in any of the surface acoustic wave resonators, the reflection grating 200 includes a plurality of reflection grating strips 210 arranged in parallel in the first direction;

[0087] In the first direction, each reflective grating 210 has a grating width W3; the grating width W3 is determined according to the first stripe period and / or the second stripe period.

[0088] Any two adjacent reflective gratings 210 form a grating spacing S3 in the first direction; the grating spacing S3 is determined according to the first stripe period and / or the second stripe period.

[0089] The size of each of the reflective gratings 210 in the second direction is greater than or equal to the size of the interdigital structure 100 in the second direction.

[0090] In a specific embodiment, the reflective grid 200 includes a plurality of reflective grid bars 210 arranged in parallel in a first direction. Figure 4-Figure 7 A plurality of structural schematic diagrams corresponding to the reflective grating 200 provided in the embodiment of the present invention are shown in FIG. Figure 4-Figure 7 As shown in the figure, in the first direction, each reflective grating 210 has a grating width W3, and a grating spacing S3 is formed between two adjacent reflective gratings 210. The determination of the grating width W3 and the grating spacing S3 is related to the first stripe period and / or the second stripe period, wherein the first stripe period is generally equal to the second stripe period.

[0091] Specifically, the value range of the grid bar width W3 can be λ / 16~λ / 4, and the value range of the grid bar spacing S3 can be λ / 16~λ / 4, where λ is the wavelength, and λ can be set to 2*the first stripe period. Preferably, the grid bar width W3 is set to be equal to the grid bar spacing S3, which is λ / 8.

[0092] Furthermore, in the second direction, the size of each reflective grating 210 is set to be larger than that of the interdigital structure 100. When the reflective grating 200 covers a larger area in the second direction than the interdigital structure 100, it can provide a complete reflective boundary for the interdigital region, reducing the ingress of laterally propagating acoustic or electromagnetic waves into the interdigital region, thereby effectively suppressing unnecessary stray waves or reflected wave interference and improving signal purity. At the same time, it can better enhance the reflection effect, improve the quality factor of the resonator, and enhance frequency selectivity, resulting in better performance of the device at the target frequency.

[0093] The material of the reflector 200 can also affect the transverse mode suppression performance. A metal with a higher density has a better transverse mode suppression effect. The metal can be a single layer or multiple layers of metal, or a bonding layer of one or more metals. Examples of the metal include aluminum, copper, silver, gold, tungsten, chromium, titanium, molybdenum, or combinations of these metals or doped metals.

[0094] By combining the first and / or second strip period to define the grid strip spacing S3 and grid strip width W3, the resonant frequency of the main propagation mode is optimized, and interference from higher-order modes is reduced, thereby improving the frequency selectivity and signal purity of the surface acoustic wave resonator. This also allows the acoustic wave energy to be concentrated on the main propagation path, reducing lateral energy leakage, improving energy utilization efficiency, and suppressing spurious modes.

[0095] like Figure 1-Figure 3 As shown in any of the above, in the surface acoustic wave resonator, the plurality of reflective gratings 210 and the first fingers 111 and the second fingers 121 form a plurality of reflective holes 220 ; the plurality of reflective holes 220 are arranged at first intervals in the first direction and at second intervals in the second direction.

[0096] The multiple reflective holes 220 have the same shape and size, and are rectangular or diamond-shaped. When the multiple reflective holes 220 are diamond-shaped, the angle between any of the reflective bars 210 and the first finger bars 111 and / or the second finger bars 121 in the first direction is in a range of 60° to 85°.

[0097] In a specific embodiment, the plurality of reflective bars 210 on both sides of the interdigital structure 100 cooperate with the first finger bars 111 and the second finger bars 121 to form a plurality of reflective holes 220. The shape of the reflective holes 220 can be rectangular, diamond, elliptical, triangular, etc. Figure 1-Figure 3 As shown in any example, when the shape of the reflective hole 220 is rectangular, the reflective grid 200 and the first finger strips 111 and / or the second finger strips 121 intersect and are perpendicular to each other in the same plane; Figure 4 As shown, when the shape of the reflective hole 220 is a diamond, the angle θ between the reflective grating 210 and the first finger 111 and / or the second finger 121 in the first direction may be in the range of 60° to 85°, and preferably 80°; Figure 5 As shown, when the shape of the reflective hole 220 is an isosceles triangle, the grid spacing S3 is the height of the isosceles triangle; Figure 6 As shown, when the shape of the reflective hole 220 is a right triangle, the grid spacing S3 is one of its right angle sides; Figure 7 As shown, when the reflective aperture 220 is elliptical, the grid spacing S3 is the length of its short side. The shape of the reflective aperture 220 can affect the suppression effect on the transverse mode. Specifically, it can be considered that the suppression ability of a rectangular reflective aperture is better than that of a diamond reflective aperture, the suppression ability of a diamond reflective aperture is better than that of an elliptical reflective aperture, the suppression ability of an elliptical reflective aperture is better than that of an isosceles triangle reflective aperture, and the suppression ability of an isosceles triangle reflective aperture is better than that of a right-angled triangle reflective aperture.

[0098] Figure 8The admittance diagram corresponding to the comparison of two resonators provided in a specific embodiment of the present invention is shown in FIG. Figure 8 , Figure 8 The horizontal axis represents frequency, the vertical axis represents admittance, the blue curve represents the admittance curve of the surface acoustic wave resonator in the prior art, and the red curve represents the admittance curve of the surface acoustic wave resonator provided in this embodiment; Figure 9 The dB value curve of the real part of admittance of two resonators provided in a specific embodiment of the present invention is shown in FIG. Figure 9 , Figure 9 The horizontal axis represents the frequency, the vertical axis represents the dB value of the real part of the admittance, the blue curve represents the dB value curve of the real part of the admittance of the surface acoustic wave resonator in the prior art, and the red curve represents the dB value curve of the real part of the admittance of the surface acoustic wave resonator provided by this embodiment, wherein the pink box can reflect the suppression performance of the longitudinal mode, and the yellow box can reflect the suppression performance of the transverse mode. Figure 8-Figure 9 It can be seen that, compared with the prior art, the resonator disclosed in the present invention can achieve better longitudinal mode suppression and transverse mode suppression effects, has good modulation performance, and can reduce the impact of interference signals.

[0099] Based on the same inventive concept, an embodiment of the present invention further provides a filter, including the surface acoustic wave resonator in the above embodiment. Therefore, the filter provided by the embodiment of the present invention also has the beneficial effects described in the above embodiment, which will not be repeated here.

[0100] It can be seen from the embodiments provided by the present invention that, in the present invention, the surface acoustic wave resonator includes a finger region and a reflection grating. In the finger region, the parallel and spaced fingers can uniformly excite the surface acoustic wave, avoiding uneven acoustic wave excitation caused by the irregular distribution of the fingers, thereby generating a clear and stable main propagation mode and improving the consistency of the frequency response. The reflection grating is arranged on both sides of the finger region, and is located in the same plane as the finger region and perpendicular to each other, so that the reflection grating can efficiently reflect the laterally propagating acoustic wave energy and guide it back to the main propagation direction, thereby improving the utilization efficiency of the acoustic wave energy and reducing the interference of the lateral mode on the resonator performance. In addition, setting the reflection grating and the finger region in the same plane can reduce the complexity of the multi-layer manufacturing process, thereby reducing alignment errors and manufacturing costs; at the same time, it can avoid the problem of interlayer scattering and improve energy utilization efficiency and signal purity.

[0101] It should be noted that the various embodiments of the present disclosure have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles, practical applications, or technical improvements to the market of the various embodiments, or to enable other persons skilled in the art to understand the various embodiments disclosed herein.

Claims

1. A surface acoustic wave resonator, characterized in that: Having a first direction and a second direction perpendicular to each other, the resonator includes: An interdigital structure comprising a first interdigital region and a second interdigital region; the first interdigital region comprises a plurality of first fingers, and the second interdigital region comprises a plurality of second fingers; a reflective grating disposed on both sides of the interdigitated structure in a first direction, the reflective grating being located in the same plane as the plurality of first fingers and the plurality of second fingers; the reflective grating intersecting the plurality of first fingers, and the reflective grating intersecting the plurality of second fingers; the first direction being parallel to an extension direction of the plurality of first fingers; In the first direction, each first finger is arranged opposite to each second finger, and an opposing distance is formed between the first finger and the second finger; In the second direction, the plurality of first fingers are arranged in parallel, and the plurality of second fingers are arranged in parallel; Wherein, the reflective grating includes a plurality of reflective grating strips arranged in parallel in the first direction; In the first direction, each reflective grating has a grating width; the grating width is determined according to the first stripe period and / or the second stripe period; the first finger has the first stripe period, and the second finger has the second stripe period; Any two adjacent reflective gratings form a grating spacing in the first direction.

2. A surface acoustic wave resonator according to claim 1, characterized in that: In the first interdigitated region, in the second direction, each of the first fingers has a first finger width, and any two adjacent first fingers in the plurality of first fingers have a first finger spacing; The sum of the first finger width and the first finger spacing is the first stripe period; the first stripe period ranges from 0.3 μm to 3.5 μm; A ratio of the first finger width to the first stripe period is a first duty cycle corresponding to the first finger; and the first duty cycle ranges from 0.4 to 0.

65.

3. A surface acoustic wave resonator according to claim 2, characterized in that: Each of the first fingers has a first finger length extending along the first direction; The length of the first fingers is determined according to the order of the first fingers in the second direction and the number of the plurality of first fingers.

4. The surface acoustic wave resonator according to claim 1, characterized in that: In the second interdigitated region, in the second direction, each of the second fingers has a second finger width, and any two adjacent second fingers in the plurality of second fingers have a second finger spacing; The sum of the second finger width and the second finger spacing is the second stripe period; the second stripe period ranges from 0.3 μm to 3.5 μm; A ratio of the second finger width to the second stripe period is a second duty cycle corresponding to the second finger; and the second duty cycle ranges from 0.4 to 0.

65.

5. The surface acoustic wave resonator according to claim 4, characterized in that: Each of the second fingers has a second finger length extending along the first direction; The length of the second fingers is determined according to the order of the second fingers in the second direction and the number of the plurality of second fingers.

6. The surface acoustic wave resonator according to claim 1, characterized in that: The interdigitated structure includes a plurality of first fingers and a plurality of opposing spacings formed between the plurality of second fingers; The plurality of opposing intervals are parallel to each other in the second direction and are staggeredly distributed around a central axis of the interdigital structure.

7. The surface acoustic wave resonator according to claim 6, characterized in that: The spacing range of the opposing spacing is 0.2 μm to 10.5 μm.

8. The surface acoustic wave resonator according to claim 1, characterized in that: The grid stripe spacing is determined according to the first stripe period and / or the second stripe period.

9. The surface acoustic wave resonator according to claim 1, characterized in that: The size of each of the reflective gratings in the second direction is greater than or equal to the size of the interdigital structure in the second direction.

10. The surface acoustic wave resonator according to claim 1, characterized in that: The plurality of reflective gratings, the first finger strips and the second finger strips form a plurality of reflective holes; The plurality of reflective holes are arranged at first intervals in the first direction and at second intervals in the second direction.

11. The surface acoustic wave resonator according to claim 10, characterized in that: The multiple reflective holes have the same shape, and are all rectangular or diamond-shaped; When the shape of the plurality of reflective holes is rhombus, the included angle between any of the reflective gratings and the first finger strips and / or the second finger strips in the first direction ranges from 60° to 85°.

12. A filter, characterized in that: The surface acoustic wave resonator according to any one of claims 1 to 11 is included.

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